PUBLIC SERVICE CO OF COLORADO
S-3, 1996-10-24
ELECTRIC & OTHER SERVICES COMBINED
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                                                   Registration No. 333-
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                _______________
                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                _______________
                       PUBLIC SERVICE COMPANY OF COLORADO
                  (Exact name of registrant as specified in its charter)
              Colorado                                   84-0296600
   (State or other jurisdiction of                   (I.R.S. employer)
    incorporation or organization)                  identification no.)
                                1225 17th Street
                           Denver, Colorado 80202-5533
                                 (303) 571-7511
               (Address, including zip code, and telephone number,
        including area code, of registrant's principal executive offices)

                                   R.C. Kelly
                         Senior Vice President, Finance,
                      Treasurer and Chief Financial Officer
                       Public Service Company of Colorado
                                1225 17th Street
                           Denver, Colorado 80202-5533
                                 (303) 571-7511
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)
                                _______________
                                   Copies to:
            J.H. Newman                      E. Ellsworth McMeen, III
         Brown & Wood LLP             LeBoeuf, Lamb, Greene & MacRae, L.L.P.
     One World Trade Center                     125 West 55th Street
       New York, NY 10048                     New York, New York 10019
                                _______________
      Approximate  date of commencement of proposed sale to the public:  At such
time or times after the  effective  date of this  Registration  Statement as the
registrant shall determine based on market conditions and other factors.

      If the only  securities  being  registered  on this Form are being offered
pursuant to dividend or interest  reinvestment plans, please check the following
box. |_|

      If any of the securities  being  registered on this Form are to be offered
on a delayed or continuous  basis  pursuant to Rule 415 under the Securities Act
of 1933,  other than  securities  offered only in  connection  with  dividend or
interest reinvestment plans, check the following box. |X|

      If this Form is filed to register  additional  securities  for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list  the  Securities  Act  registration  statement  number  of the  earlier
effective registration statement for the same offering. |_|

      If this Form is a  post-effective  amendment filed pursuant to Rule 462(c)
under the  Securities  Act,  check the following box and list the Securities Act
registration  statement number of the earlier effective  registration  statement
for the same offering.
|_|

     If delivery of the  prospectus is expected to be made pursuant to Rule 434,
please check the following box. |_|
                                  ____________

<PAGE>
<TABLE>
<CAPTION>

                        CALCULATION OF REGISTRATION FEE
================================================================================
                                            Proposed    Proposed
  Title of Each Class of     Amount to be    Maximum     Maximum      Amount of
 Securities to be Register    Registered    Offering   Aggregate   Registration
                                              Price     Offering         Fee
                                          Per Unit (1)  Price (1)
- --------------------------------------------------------------------------------
<S>                          <C>             <C>     <C>              <C>

First Collateral Trust Bonds
(being one or more series  
of medium-term notes) . .    $400,000,000    100%    $400,000,000     $121,213

================================================================================
(1)    Estimated solely for the purpose of calculating the registration fee.
</TABLE>          
                                   _________

      The registrant hereby amends this  Registration  Statement on such date or
dates as may be necessary to delay its effective date until the registrant shall
file a further  amendment  which  specifically  states  that  this  Registration
Statement shall  thereafter  become effective in accordance with Section 8(a) of
the  Securities  Act of 1933 or until the  Registration  Statement  shall become
effective  on such  date  as the  Securities  and  Exchange  Commission,  acting
pursuant to said Section 8(a), may determine.

<PAGE>

                  SUBJECT TO COMPLETION, DATED OCTOBER 24, 1996

PROSPECTUS SUPPLEMENT
(To Prospectus dated        , 1996)
                                 $250,000,000
                                    [LOGO]
                      PUBLIC SERVICE COMPANY OF COLORADO

                       Secured Medium-Term Notes, Series B
                (being a series of First Collateral Trust Bonds)
                         Due From Nine Months To Thirty
                            Years From Date of Issue

                               ------------------

      Public Service  Company of Colorado (the "Company") may offer from time to
time up to $250,000,000  aggregate  principal amount of its Secured  Medium-Term
Notes,  Series B (being a series of First Collateral Trust Bonds) (the "Notes").
Each Note will mature on a date from nine  months to thirty  years from its date
of issue,  as specified in the  applicable  pricing  supplement  hereto (each, a
"Pricing  Supplement"),  and may be subject to  redemption  at the option of the
Company or repayment at the option of the Holder thereof, in each case, in whole
or in part,  prior to its Stated  Maturity,  and may be  subject  to  redemption
pursuant to sinking fund or other mandatory redemption provisions,  if specified
in the  applicable  Pricing  Supplement.  The Notes  will be  issued in  minimum
denominations of $100,000 and any greater amount that is an integral multiple of
$1,000.

      Each Note will bear  interest at a fixed rate.  Interest on each Note will
accrue from its date of issue and, unless otherwise  specified in the applicable
Pricing  Supplement,  will be payable  semiannually in arrears on February 1 and
August 1 of each year and at Maturity. Notes may also be issued that do not bear
any interest currently or that bear interest at a below market rate.

      The variable  terms of each Note will be established by the Company on the
date of issue  of such  Note and will be  specified  in the  applicable  Pricing
Supplement. Interest rates and other terms of the Notes are subject to change by
the Company,  but no such change will affect any Note previously issued or as to
which an offer to purchase has been accepted by the Company.

      Each Note will be issued in book-entry  form (a  "Book-Entry  Note") or in
fully registered  certificated form (a "Certificated Note"), as specified in the
applicable Pricing  Supplement.  Each Book-Entry Note will be represented by one
or more fully registered global securities (the "Global  Securities")  deposited
with or on behalf of The  Depository  Trust  Company  (or such other  depositary
identified  in  the  applicable  Pricing   Supplement)  (the  "Depositary")  and
registered in the name of the Depositary or the Depositary's nominee.  Interests
in the  Global  Securities  will be shown  on,  and  transfers  thereof  will be
effected only through, records maintained by the Depositary (with respect to its
participants)  and the  Depositary's  participants  (with  respect to beneficial
owners).  Except  in  limited  circumstances,   Book-Entry  Notes  will  not  be
exchangeable for Certificated Notes.

  THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
 EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
   AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
    ACCURACY OR ADEQUACY OF THIS PROSPECTUS SUPPLEMENT, THE PROSPECTUS OR ANY
  SUPPLEMENT HERETO. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

==============================================================+=================
                     Price to      Agents' Discounts            Proceeds to
                     Public(1)   and Commissions(1)(2)        Company (1)(3)
- --------------------------------------------------------------------------------
 Per Note........      100%         .125%-.750%              99.875%-99.250%
- --------------------------------------------------------------------------------
 Total ..........  $250,000,000  $312,500-$1,875,000   $249,267,500-$247,705,000
================================================================================

(1)  Merrill Lynch & Co., Merill Lynch, Pierce,  Fenner & Smith Incorporated and
     Goldman,  Sachs & Co. (the "Agents"),  individually or in a syndicate,  may
     purchase Notes, as principal,  from the Company for resale to investors and
     other purchasers at varying prices relating to prevailing  market prices at
     the  time of  resale  as  determined  by the  applicable  Agent  or,  if so
     specified  in the  applicable  Pricing  Supplement,  for  resale at a fixed
     offering  price.  Unless  otherwise  specified  in the  applicable  Pricing
     Supplement,  any Note sold to an Agent as  principal  will be  purchased by
     such Agent at a price equal to 100% of the principal  amount thereof less a
     percentage of the principal amount equal to the commission applicable to an
     agency  sale (as  described  below)  of a Note of  identical  maturity.  If
     requested by the Company and agreed to by an Agent,  such Agent may utilize
     its reasonable efforts on an agency basis to solicit offers to purchase the
     Notes at 100% of the principal amount thereof,  unless otherwise  specified
     in the applicable Pricing Supplement.  The Company will pay a commission to
     an Agent,  ranging from .125% to .750% of the  principal  amount of a Note,
     depending  upon its stated  maturity,  sold through an Agent.  See "Plan of
     Distribution".

(2)  The Company has agreed to indemnify the Agents against certain liabilities,
     including  liabilities  under the Securities  Act of 1933, as amended.  See
     "Plan of Distribution."

(3)  Before deducting expenses payable by the Company estimated at $421,213.

                                 ---------------

      The Notes are being offered on a continuing  basis directly by the Company
or by the Company to or through the Agents.  Unless  otherwise  specified in the
applicable  Pricing  Supplement,  the Notes will not be listed on any securities
exchange.  There is no assurance  that the Notes offered hereby will be sold or,
if sold, that there will be a secondary market for the Notes or liquidity in the
secondary  market if one develops.  The Company  reserves the right to cancel or
modify the offer made hereby  without  notice.  The  Company or an Agent,  if it
solicits the offer on an agency basis, may reject any offer to purchase Notes in
whole or in part. See "Plan of Distribution".

                               -------------------

Merrill Lynch & Co.                                       Goldman, Sachs & Co.
                               -------------------

            The date of this Prospectus Supplement is ________, 1996.


<PAGE>
Information   contained  herein  is  subject  to  completion  or  amendment.   A
registration  statement  relating  to these  securities  has been filed with the
Securities  and Exchange  Commission.  These  securities may not be sold nor may
offers to buy be accepted prior to the time the registration  statement  becomes
effective.   This  preliminary   prospectus   supplement  and  the  accompanying
prospectus shall not constitute an offer to sell or the solicitation of an offer
to buy nor  shall  there be any sale of these  securities  in any State in which
such offer,  solicitation  or sale would be unlawful  prior to  registration  or
qualification under the securities laws of any such State.

<PAGE>


      IN CONNECTION WITH AN OFFERING OF NOTES PURCHASED BY ONE OR MORE AGENTS AS
PRINCIPAL ON A FIXED  OFFERING  PRICE BASIS,  SUCH  AGENT(S) MAY  OVER-ALLOT  OR
EFFECT  TRANSACTIONS  WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF NOTES AT A
LEVEL  ABOVE  THAT  WHICH  MIGHT  OTHERWISE  PREVAIL  IN THE OPEN  MARKET.  SUCH
STABILIZING, IF COMMENCED, MAY BE DISCONTINUED AT ANY TIME.

                              --------------------

                     SUPPLEMENTAL DESCRIPTION OF THE NOTES

      The  following   description  of  the   particular   terms  of  the  Notes
supplements,  and to the extent inconsistent therewith replaces, the description
of the general terms and provisions of the Notes set forth under "Description of
the New Bonds" in the  accompanying  Prospectus,  to which  reference  is hereby
made.  Certain  capitalized terms used herein are defined under  "Description of
the New Bonds" in the accompanying Prospectus.

General

      The Notes  will be  issued  from  time to time in an  aggregate  principal
amount not to exceed  $250,000,000,  as a series of First Collateral Trust Bonds
under the 1993 Mortgage. The Notes will be issued on the basis of Class A Bonds,
which are to be issued  under the 1939  Mortgage.  See  "Description  of the New
Bonds" in the accompanying Prospectus.

      The Notes will be issued in fully  registered form only,  without coupons.
Each Note will be issued as a Book-Entry  Note  represented by one or more fully
registered  Global  Securities or as a  Certificated  Note.  Except as set forth
herein  under  "Book-Entry  Notes"  or in any  Pricing  Supplement  relating  to
specific  Notes,  the Notes will not be  issuable  as  Certificated  Notes.  The
authorized  denominations  of the Notes will be $100,000 and any greater  amount
that is an integral multiple of $1,000.

      Each Note will mature on a date from nine months to thirty  years from its
date of  issue.  Each Note may also be  subject  to  redemption  prior to Stated
Maturity at the option of the Company or at the option of the Holder, and may be
subject to  redemption  pursuant to sinking fund or other  mandatory  redemption
provisions, all as may be set forth in the applicable Pricing Supplement.

      The Pricing  Supplement  relating to a Note will  describe  the  following
terms:  (i) the price  (expressed  as a percentage  of the  aggregate  principal
amount  thereof) at which such Note will be issued;  (ii) the date on which such
Note will be issued (the  "Original  Issue Date");  (iii) the date on which such
Note will mature (the "Stated Maturity");  (iv) the rate per annum at which such
Note will bear interest;  (v) whether such Note may be redeemed at the option of
the Company  prior to Stated  Maturity as  described  under  "Redemption  at the
Option of the  Company"  below  and,  if so,  the  provisions  relating  to such
redemption;  (vi) the  obligation of the Company to redeem such Note pursuant to
any sinking fund or other  mandatory  redemption  provisions  applicable to such
Note;  (vii) any  provisions for the repayment of such Note at the option of the
Holder as described  under  "Repayment at the Option of the Holder"  below;  and
(vii) any other special terms of such Notes.

      Interest rates offered by the Company with respect to the Notes may differ
depending upon,  among other factors,  the aggregate  principal  amount of Notes
purchased in any single  transaction.  Notes with different variable terms other
than interest  rates may also be offered  concurrently  to different  investors.
Interest  rates and other  terms of Notes are  subject to change by the  Company
from time to time, but no such change will affect any Note previously  issued or
as to which an offer to purchase has been accepted by the Company.

Payment of Principal and Interest

      Each Note  will bear  interest,  computed  on the basis of a 360-day  year
consisting of twelve 30-day months, from its Original Issue Date at the rate per
annum stated on the face thereof and in the applicable  Pricing Supplement until
the  principal  amount  thereof  is paid or duly  made  available  for  payment.
Interest on each Note

                                      S-2

<PAGE>



will be payable semiannually in arrears on February 1 and August 1 in each year,
or such other dates as may be specified  in the  applicable  Pricing  Supplement
(each such date being  hereinafter  called an  "Interest  Payment  Date") and at
maturity (whether at Stated Maturity, by declaration of acceleration,  upon call
for redemption or otherwise, hereinafter "Maturity"). Unless otherwise specified
in the  applicable  Pricing  Supplement,  interest  payments  will be made in an
amount  equal  to the  interest  accrued  from  and  including  the  immediately
preceding  Interest  Payment Date in respect of which  interest has been paid or
duly made  available for payment (or from and including the Original Issue Date,
if no  interest  has  been  paid or duly  made  available  for  payment)  to but
excluding the applicable  Interest Payment Date or the Stated  Maturity,  as the
case may be.

      Payments  of  interest  on the  Notes  (other  than  interest  payable  at
Maturity) will be made, except as provided below, by check mailed to the Holders
of such Notes as of the Record Date (as hereinafter defined) next preceding each
Interest  Payment  Date,  except  that  (a) in the  case  of  Global  Securities
representing  Book-Entry  Notes,  such payment will be made in  accordance  with
arrangements then in effect among the Company, the 1993 Mortgage Trustee and the
Depository,  (b) if the Original Issue Date of a Note is after a Record Date and
before the corresponding Interest Payment Date, the first payment of interest on
such  Note  will be made on the next  succeeding  Interest  Payment  Date to the
Holder of such Note on the Record Date with respect to such succeeding  Interest
Payment Date and (c) if the Company  defaults in the payment of the interest due
on any Note on any  Interest  Payment  Date,  such  defaulted  interest  will be
payable to the Holder of such Note as of a Special Record Date fixed by the 1993
Mortgage Trustee, which shall be not more than 30 days and not less than 10 days
prior to the date of  payment  of such  defaulted  interest,  or  payable to the
Holder in such other manner as permitted by the 1993 Mortgage.  See  "Book-Entry
Notes".  Unless otherwise  specified in the applicable Pricing  Supplement,  the
"Record Date" with respect to each Interest  Payment Date will be the January 15
or July 15, as the case may be, next preceding such Interest Payment Date.

      Unless  otherwise  specified in the  applicable  Pricing  Supplement,  the
principal of, premium, if any, and interest on any Note payable at Maturity will
be paid upon surrender thereof at the office of the 1993 Mortgage Trustee.

      If the date of making any payment with respect to a Note is not a Business
Day,  such  payment  may be made on the next  succeeding  Business  Day,  and if
payment is made or duly provided for on such succeeding Business Day no interest
shall accrue for the period from and after such Interest Payment Date. "Business
Day" means any day other than a Saturday or Sunday,  which is not a day on which
banking  institutions  or trust  companies in The City of New York are generally
authorized or required by law, regulation or executive order to remain closed.

Redemption at the Option of the Company

      Unless otherwise specified in the applicable Pricing Supplement, the Notes
will not be subject to any sinking  fund.  The Notes will be  redeemable  at the
option of the Company  prior to Stated  Maturity  only if an Initial  Redemption
Date is specified in the applicable  Pricing  Supplement.  If so specified,  the
Notes will be subject to  redemption at the option of the Company on any date on
and after the applicable  Initial  Redemption Date in whole or from time to time
in part in increments of $1,000  (provided that any remaining  principal  amount
thereof shall be at least  $100,000),  at the  applicable  Redemption  Price (as
hereinafter defined),  together with unpaid interest accrued thereon to the date
of redemption,  on written notice given to the Holders  thereof not more than 60
nor less than 30 calendar days prior to the date of redemption and in accordance
with the provisions of the 1993 Mortgage.  "Redemption Price", with respect to a
Note, means an amount equal to the Initial  Redemption  Percentage  specified in
the  applicable  Pricing  Supplement  (as  adjusted  by  the  Annual  Redemption
Percentage Reduction,  if applicable)  multiplied by the unpaid principal amount
to be redeemed. The Initial Redemption Percentage,  if any, applicable to a Note
shall decline at each  anniversary of the Initial  Redemption  Date by an amount
equal to the applicable Annual Redemption  Percentage  Reduction,  if any, until
the  Redemption  Price is equal to 100% of the  unpaid  principal  amount  to be
redeemed.


                                      S-3

<PAGE>



Repayment at the Option of the Holder

      The Notes will be  repayable  by the  Company at the option of the Holders
thereof  prior  to the  Stated  Maturity  thereof  only if one or more  Optional
Repayment  Dates are  specified  in the  applicable  Pricing  Supplement.  If so
specified,  the Notes will be subject to  repayment at the option of the Holders
thereof on any Optional  Repayment Date in whole or from time to time in part in
increments of $1,000 (provided that any remaining principal amount thereof shall
be at  least  $100,000),  at a  repayment  price  equal  to 100%  of the  unpaid
principal amount to be repaid,  together with unpaid interest accrued thereon to
the date of  repayment.  For any Note to be repaid,  such Note must be received,
together  with the form  thereon  entitled  "Option  to  Elect  Repayment"  duly
completed, at the office of the 1993 Mortgage Trustee, not more than 60 nor less
than 30 calendar days prior to the date of repayment. Exercise of such repayment
option by the Holder will be irrevocable.

      Only the Depositary may exercise the repayment option in respect of Global
Securities  representing Book- Entry Notes.  Accordingly,  Beneficial Owners (as
hereinafter defined) of Global Securities that desire to have all or any portion
of the  Book-Entry  Notes  represented  by such  Global  Securities  repaid must
instruct the Participant (as hereinafter  defined)  through which they own their
interest to direct the  Depositary  to exercise  the  repayment  option on their
behalf by delivering  the related Global  Security and duly  completed  election
form to the 1993  Mortgage  Trustee as  aforesaid.  In order to ensure that such
Global Security and election form are received by the 1993 Mortgage Trustee on a
particular day, the applicable Beneficial Owner must so instruct the Participant
through  which it owns its  interest  before  such  Participant's  deadline  for
accepting  instructions  for  that  day.  Different  firms  may  have  different
deadlines  for  accepting   instructions  from  their  customers.   Accordingly,
Beneficial  Owners should consult the Participants  through which they own their
interest for the respective  deadlines for such  Participants.  All instructions
given to Participants from Beneficial  Owners of Global  Securities  relating to
the option to elect  repayment shall be  irrevocable.  In addition,  at the time
such  instructions  are  given,  each  such  Beneficial  Owner  shall  cause the
Participant  through  which it owns its  interest  to transfer  such  Beneficial
Owner's  interest in the Global Security or Securities  representing the related
Book-Entry Notes, on the Depositary's records, to the 1993 Mortgage Trustee. See
"Book-Entry Notes".

      If applicable,  the Company will comply with the  requirements  of Section
14(e) of the Securities  Exchange Act of 1934, as amended (the "Exchange  Act"),
and  the  rules  promulgated  thereunder,  and  any  other  securities  laws  or
regulations in connection with any such repayment.

      The Company may at any time  purchase  Notes at any price or prices in the
open  market  or  otherwise.  Notes so  purchased  by the  Company  may,  at the
discretion of the Company,  be held,  resold or  surrendered  to the Trustee for
cancellation.

Book-Entry Notes

      The Company has established a depositary  arrangement  with The Depository
Trust  Company  with  respect to the  Book-Entry  Notes,  the terms of which are
summarized   below.   Any  additional  or  differing  terms  of  the  depositary
arrangement  with  respect  to the  Book-Entry  Notes will be  described  in the
applicable Pricing Supplement.

      Upon  issuance,  all  Book-Entry  Notes  of like  tenor  and  terms  up to
$200,000,000  aggregate  principal amount will be represented by a single Global
Security.  Each Global Security representing  Book-Entry Notes will be deposited
with, or on behalf of, the  Depositary and will be registered in the name of the
Depositary or a nominee of the Depositary. No Global Security may be transferred
except as a whole by a nominee of the Depositary to the Depositary or to another
nominee of the  Depositary,  or by the Depositary or such nominee to a successor
of the Depositary or a nominee of such successor.

      So long as the  Depositary  or its  nominee is the  registered  owner of a
Global Security,  the Depositary or its nominee, as the case may be, will be the
sole Holder of the Book-Entry Notes  represented  thereby for all purposes under
the 1993 Mortgage.  Except as otherwise provided below, the Beneficial Owners of
the Global  Security or  Securities  representing  Book-Entry  Notes will not be
entitled  to receive  physical  delivery of  Certificated  Notes and will not be
considered the Holders  thereof for any purpose under the 1993 Mortgage,  and no
Global

                                      S-4

<PAGE>



Security  representing  Book-Entry  Notes shall be exchangeable or transferable.
Accordingly, each Beneficial Owner must rely on the procedures of the Depositary
and, if such  Beneficial  Owner is not a  Participant,  on the procedures of the
Participant  through which such  Beneficial  Owner owns its interest in order to
exercise any rights of a Holder under such Global Security or the 1993 Mortgage.
The laws of some  jurisdictions  require that certain  purchasers  of securities
take physical delivery of such securities in certificated  form. Such limits and
laws may  impair  the  ability  to  transfer  beneficial  interests  in a Global
Security representing Book-Entry Notes.

     Unless  otherwise  specified in the  applicable  Pricing  Supplement,  each
Global  Security   representing   Book-Entry  Notes  will  be  exchangeable  for
Certificated  Notes  of  like  tenor  and  terms  and  of  differing  authorized
denominations in a like aggregate  principal amount,  only if (i) the Depositary
notifies  the Company and the 1993  Mortgage  Trustee  that it is  unwilling  or
unable to  continue  as  Depositary  for the Global  Securities  or the  Company
becomes aware that the Depositary has ceased to be a clearing agency  registered
under  the  Exchange  Act and,  in any such  case,  the  Company  shall not have
appointed a successor  to the  Depositary  within 90 days  thereafter,  (ii) the
Company, in its sole discretion,  determines that the Global Securities shall be
exchangeable  for  Certificated  Notes or (iii) an Event of  Default  shall have
occurred and be  continuing  with respect to the Notes under the 1993  Mortgage,
the 1993 Mortgage  Trustee shall have given notice  thereof to the Holders,  and
there shall have been delivered to the Company and the 1993 Mortgage  Trustee an
Opinion of Counsel to the effect that the interests of the beneficial  owners of
the Global  Securities  will be  materially  impaired  unless such owners become
Holders of Certificated  Notes. Upon any such exchange,  the Certificated  Notes
shall be registered in the names of the Beneficial Owners of the Global Security
or Securities  representing  Book-Entry Notes,  which names shall be provided by
the Depositary's  relevant Participants (as identified by the Depositary) to the
1993 Mortgage Trustee.

      The following is based on information furnished by the Depositary:

            The Depositary will act as securities  depository for the Book-Entry
      Notes. The Book-Entry Notes will be issued as fully registered  securities
      registered  in the  name  of  Cede  & Co.  (the  Depositary's  partnership
      nominee).  One fully  registered  Global  Security will be issued for each
      issue of Book-Entry Notes, each in the aggregate  principal amount of such
      issue,  and  will be  deposited  with the  Depositary.  If,  however,  the
      aggregate principal amount of any issue exceeds  $200,000,000,  one Global
      Security  will be issued with  respect to each  $200,000,000  of principal
      amount and an  additional  Global  Security will be issued with respect to
      any remaining principal amount of such issue.

            The Depositary is a  limited-purpose  trust company  organized under
      the New York Banking Law, a "banking  organization"  within the meaning of
      the New York  Banking  Law,  a member of the  Federal  Reserve  System,  a
      "clearing  corporation"  within  the  meaning  of  the  New  York  Uniform
      Commercial  Code,  and a  "clearing  agency"  registered  pursuant  to the
      provisions  of Section  17A of the  Exchange  Act.  The  Depositary  holds
      securities  that  its  participants   ("Participants")  deposit  with  the
      Depositary.   The  Depositary  also   facilitates  the  settlement   among
      Participants of securities transactions, such as transfers and pledges, in
      deposited securities through electronic computerized book-entry changes in
      Participants' accounts, thereby eliminating the need for physical movement
      of securities certificates. Direct Participants of the Depositary ("Direct
      Participants")  include  securities  brokers  and dealers  (including  the
      Agents),  banks, trust companies,  clearing corporations and certain other
      organizations.  The  Depositary  is  owned  by  a  number  of  its  Direct
      Participants and by the New York Stock Exchange,  Inc., the American Stock
      Exchange,  Inc., and the National Association of Securities Dealers,  Inc.
      Access to the  Depositary's  system is also  available  to others  such as
      securities  brokers  and  dealers,  banks and trust  companies  that clear
      through or maintain a custodial  relationship  with a Direct  Participant,
      either  directly  or  indirectly  ("Indirect  Participants").   The  rules
      applicable to the  Depositary  and its  Participants  are on file with the
      Securities and Exchange Commission.

            Purchases of Book-Entry Notes under the Depositary's  system must be
      made by or through  Direct  Participants,  which will receive a credit for
      such Book-Entry Notes on the Depositary's  records. The ownership interest
      of each actual  purchaser of each Book-Entry Note  represented by a Global
      Security  ("Beneficial Owner") is in turn to be recorded on the records of
      Direct Participants and Indirect Participants.  Beneficial Owners will not
      receive written confirmation from the Depositary of their

                                      S-5

<PAGE>



      purchase,   but  Beneficial   Owners  are  expected  to  receive   written
      confirmations  providing  details of the transaction,  as well as periodic
      statements of their  holdings,  from the Direct  Participants  or Indirect
      Participants   through  which  such  Beneficial  Owner  entered  into  the
      transaction.  Transfers  of  ownership  interests  in  a  Global  Security
      representing  Book-Entry  Notes are to be  accomplished by entries made on
      the  books  of  Participants   acting  on  behalf  of  Beneficial  Owners.
      Beneficial Owners of a Global Security representing  Book-Entry Notes will
      not receive  Certificated  Notes  representing  their ownership  interests
      therein,  except in the event that use of the  book-entry  system for such
      Book-Entry Notes is discontinued.

            To   facilitate   subsequent   transfers,   all  Global   Securities
      representing  Book-Entry  Notes which are deposited with, or on behalf of,
      the  Depositary are  registered in the name of the  Depositary's  nominee,
      Cede & Co. The  deposit of Global  Securities  with,  or on behalf of, the
      Depositary  and  their  registration  in the name of Cede & Co.  effect no
      change in beneficial  ownership.  The  Depositary  has no knowledge of the
      actual  Beneficial  Owners  of  the  Global  Securities  representing  the
      Book-Entry  Notes; the  Depositary's  records reflect only the identity of
      the  Direct  Participants  to whose  accounts  such  Book-Entry  Notes are
      credited,  which may or may not be the Beneficial Owners. The Participants
      will remain responsible for keeping account of their holdings on behalf of
      their customers.

            Conveyance of notices and other  communications by the Depositary to
      Direct Participants, by Direct Participants to Indirect Participants,  and
      by Direct Participants and Indirect Participants to Beneficial Owners will
      be  governed  by  arrangements  among them,  subject to any  statutory  or
      regulatory requirements as may be in effect from time to time.

            Neither  the  Depositary  nor Cede & Co.  will  consent or vote with
      respect to the Global Securities  representing the Book-Entry Notes. Under
      its usual procedures, the Depositary mails an Omnibus Proxy to the Company
      as soon as possible  after the  applicable  record date. The Omnibus Proxy
      assigns  Cede  &  Co.'s  consenting  or  voting  rights  to  those  Direct
      Participants  to whose accounts the  Book-Entry  Notes are credited on the
      applicable  record date  (identified in a listing  attached to the Omnibus
      Proxy).

            Principal, premium, if any, and/or interest, if any, payments on the
      Global  Securities  representing  the  Book-Entry  Notes  will  be made in
      immediately  available funds to the Depositary.  The Depositary's practice
      is to credit Direct Participants'  accounts on the applicable payment date
      in accordance  with their  respective  holdings shown on the  Depositary's
      records  unless the  Depositary  has  reason to  believe  that it will not
      receive  payment on such date.  Payments  by  Participants  to  Beneficial
      Owners will be governed by standing  instructions and customary practices,
      as is the case with  securities  held for the  accounts  of  customers  in
      bearer form or registered in "street name", and will be the responsibility
      of such  Participant and not of the Depositary,  the 1993 Mortgage Trustee
      or the Company, subject to any statutory or regulatory requirements as may
      be in effect from time to time.  Payment of  principal,  premium,  if any,
      and/or interest,  if any, to the Depositary is the  responsibility  of the
      Company and the 1993 Mortgage  Trustee,  disbursement  of such payments to
      Direct  Participants  shall be the  responsibility of the Depositary,  and
      disbursement  of such  payments  to the  Beneficial  Owners  shall  be the
      responsibility of Direct Participants and Indirect Participants.

            If  applicable,  redemption  notices  shall be sent to Cede & Co. If
      less than all of the  Book-Entry  Notes of like  tenor and terms are being
      redeemed,  the Depositary's  practice is to determine by lot the amount of
      the interest of each Direct Participant in such issue to be redeemed.

            A Beneficial  Owner shall give notice of any option to elect to have
      its Book-Entry Notes repaid by the Company,  through its  Participant,  to
      the 1993 Mortgage  Trustee,  and shall effect  delivery of such Book-Entry
      Notes by causing  the Direct  Participant  to transfer  the  Participant's
      interest in the Global Security or Securities representing such Book-Entry
      Notes, on the  Depositary's  records,  to the 1993 Mortgage  Trustee.  The
      requirement for physical delivery of Book-Entry Notes in connection with a
      demand for repayment will be deemed satisfied when the ownership rights in
      the Global Security or Securities  representing  such Book-Entry Notes are
      transferred by Direct Participants on the Depositary's records.


                                      S-6

<PAGE>



            The Depositary may discontinue  providing its services as securities
      depository  with  respect  to the  Book-Entry  Notes at any time by giving
      reasonable notice to the Company or the 1993 Mortgage Trustee.  Under such
      circumstances,  in the event that a successor securities depository is not
      obtained, Certificated Notes are required to be printed and delivered.

      The  Company  may decide to  discontinue  use of the system of  book-entry
transfers through the Depositary (or a successor securities depository). In that
event, Certificated Notes will be printed and delivered.

      The  information  in  this  section  concerning  the  Depositary  and  the
Depositary's  system has been obtained from sources that the Company believes to
be reliable, but the Company takes no responsibility for the accuracy thereof.

      None of the Company, the 1993 Mortgage Trustee or any agent for payment on
or   registration   of   transfer  or  exchange  of  the  Notes  will  have  any
responsibility  or  liability  for any  aspect  of the  records  relating  to or
payments  made on account of  beneficial  interests  in such  Global Note or for
maintaining,  supervising or reviewing any records  relating to such  beneficial
interests.


                                      S-7

<PAGE>



                             PLAN OF DISTRIBUTION

      The Notes are being offered on a continuing basis for sale directly by the
Company or by the  Company to or through  Merrill  Lynch & Co.,  Merrill  Lynch,
Pierce, Fenner & Smith Incorporated and Goldman, Sachs & Co. (the "Agents"). The
Agents,  individually or in a syndicate, may purchase Notes, as principal,  from
the Company from time to time for resale to investors  and other  purchasers  at
varying  prices  relating to  prevailing  market prices at the time of resale as
determined by the applicable Agent or, if so specified in the applicable Pricing
Supplement,  for resale at a fixed offering  price.  If agreed to by the Company
and an Agent,  such Agent may also utilize its  reasonable  efforts on an agency
basis to solicit  offers to purchase the Notes at 100% of the  principal  amount
thereof,  unless otherwise specified in the applicable Pricing  Supplement.  The
Company  will pay a commission  to an Agent,  ranging from .125% to .750% of the
principal amount of each Note, depending upon its stated maturity,  sold through
such Agent as an agent of the Company.

      Unless otherwise specified in the applicable Pricing Supplement,  any Note
sold to an Agent as  principal  will be purchased by such Agent at a price equal
to 100% of the  principal  amount  thereof  less a percentage  of the  principal
amount  equal  to the  commission  applicable  to an  agency  sale  of a Note of
identical maturity. An Agent may sell Notes it has purchased from the Company as
principal to certain  dealers  less a concession  equal to all or any portion of
the discount  received in connection  with such purchase.  Such Agent may allow,
and such dealers may reallow,  a discount to certain  other  dealers.  After the
initial offering of Notes, the offering price (in the case of Notes to be resold
on a fixed offering price basis),  the  concession  and the  reallowance  may be
changed.

      The Company  reserves  the right to  withdraw,  cancel or modify the offer
made hereby  without  notice and may reject  offers in whole or in part (whether
placed directly with the Company or through an Agent).  Each Agent will have the
right, in its discretion reasonably exercised, to reject in whole or in part any
offer to purchase Notes received by it on an agency basis.

      Unless otherwise specified in the applicable Pricing  Supplement,  payment
of the  purchase  price of the Notes will be required to be made in  immediately
available funds in The City of New York on the date of settlement.

      Upon issuance,  the Notes will not have an established trading market. The
Notes will not be listed on any securities exchange. The Agents may from time to
time  purchase and sell Notes in the  secondary  market,  but the Agents are not
obligated to do so, and there can be no assurance that there will be a secondary
market for the Notes or that there will be liquidity in the secondary  market if
one develops.  From time to time, the Agents may make a market in the Notes, but
the Agents are not  obligated  to do so and may  discontinue  any  market-making
activity at any time.

      The Agents may be deemed to be  "underwriters"  within the  meaning of the
Securities  Act of 1933,  as amended  (the  "Securities  Act").  The Company has
agreed  to  indemnify  the  Agents  against   certain   liabilities   (including
liabilities  under the Securities  Act). The Company has agreed to reimburse the
Agents for certain other expenses.

      In the ordinary  course of its business,  the Agents and their  affiliates
have engaged and may in the future engage in investment and  commercial  banking
transactions with the Company and certain of its affiliates.



                                      S-8


<PAGE>

                  SUBJECT TO COMPLETION, DATED OCTOBER 24, 1996

PROSPECTUS
                                  $400,000,000

                                     [Logo]

                          FIRST COLLATERAL TRUST BONDS

                       PUBLIC SERVICE COMPANY OF COLORADO

                                 ---------------

      Public Service Company of Colorado (the  "Company")  intends to offer from
time  to  time  up to  $400,000,000  aggregate  principal  amount  of its  First
Collateral  Trust  Bonds in one or more  series of  medium-term  notes (the "New
Bonds"), on terms to be determined at the time or times of sale.

      For each  offering  of the New Bonds for which  this  Prospectus  is being
delivered,   there  will  be  an  accompanying  Prospectus  Supplement  (each  a
"Prospectus  Supplement") that will set forth where applicable,  with respect to
the New Bonds,  the series  designation,  the aggregate  principal amount of the
series,  the maturity  date or dates,  the  interest  rate or rates and times of
payment  of  interest,  the  provisions  for  redemption,   if  any,  and  other
provisions,  together with the initial  public  offering  price and the terms of
offering of such New Bonds.

      The New Bonds may be sold by the Company through  underwriters or dealers,
directly by the  Company or through  agents for  offering  pursuant to the terms
fixed at the time of sale. See "PLAN OF DISTRIBUTION" herein.

                                 ---------------

          THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE
      SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION
     NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
                     COMMISSION PASSED UPON THE ACCURACY OR
                 ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION
                     TO THE CONTRARY IS A CRIMINAL OFFENSE.





           The date of this Prospectus is ________ __, 1996.


<PAGE>

Information   contained  herein  is  subject  to  completion  or  amendment.   A
registration  statement  relating  to these  securities  has been filed with the
Securities  and Exchange  Commission.  These  securities may not be sold nor may
offers to buy be accepted prior to the time the registration  statement  becomes
effective.  This  prospectus  shall  not  constitute  an  offer  to  sell or the
solicitation of an offer to buy nor shall there be any sale of these  securities
in any State in which such offer,  solicitation  or sale would be unlawful prior
to registration or qualification under the securities laws of any such State.


<PAGE>


                             AVAILABLE INFORMATION

      The Company is subject to the informational requirements of the Securities
Exchange  Act of 1934,  as  amended  (the  "Exchange  Act"),  and in  accordance
therewith  files  reports,  proxy  statements  and  other  information  with the
Securities  and Exchange  Commission  (the "SEC") and the New York,  Chicago and
Pacific Stock Exchanges.  Such reports,  proxy statements and other  information
can be inspected and copied at the public reference facilities maintained by the
SEC at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C., and
at the following  regional  offices of the SEC: New York Regional  Office,  13th
Floor,  Seven World Trade Center,  New York, New York, and the Chicago  Regional
Office, 14th Floor, 500 West Madison Street, Chicago,  Illinois.  Copies of this
material  can also be obtained  at  prescribed  rates from the Public  Reference
Section of the SEC at its principal office at Judiciary Plaza, 450 Fifth Street,
N.W.,  Washington,  D.C.  20549 or from the SEC's Web site at  "http://www.gov".
Certain of the  Company's  securities  are listed on the New York,  Chicago  and
Pacific Stock Exchanges and such reports, proxy statements and other information
can also be inspected and copied at the offices of the New York Stock  Exchange,
located on the 7th Floor, 20 Broad Street, New York, New York; the Chicago Stock
Exchange,  located  on the  12th  Floor,  440  South  LaSalle  Street,  Chicago,
Illinois;  and the  Pacific  Stock  Exchange,  located at 301 Pine  Street,  San
Francisco, California.

                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

      The  Company  hereby   incorporates  herein  by  reference  the  following
documents  which have been filed by the  Company  with the SEC  pursuant  to the
Exchange Act:

     1.  Annual Report on Form 10-K for the year ended December 31, 1995.
     2.  Quarterly Report on Form 10-Q for the quarter ending March 31, 1996.
     3.  Quarterly Report on Form 10-Q for the quarter ending June 30, 1996.
     4.  Current Reports on Form 8-K dated January 18, 1996, January 31, 1996
         and May 21, 1996.

      All documents filed by the Company with the SEC pursuant to Section 13(a),
13(c),  14 or 15(d) of the  Exchange  Act after the date hereof and prior to the
termination  of the  offering  made  hereby  shall be deemed to be  incorporated
herein by reference and to be a part hereof from the respective  dates of filing
thereof.  The  documents  incorporated  or deemed to be  incorporated  herein by
reference are sometimes  hereinafter  called the "Incorporated  Documents".  Any
statement  contained in an Incorporated  Document shall be deemed to be modified
or superseded for all purposes to the extent that a statement  contained  herein
or in any  Prospectus  Supplement  or in  any  subsequently  filed  Incorporated
Document  modifies or supersedes  such  statement.  Any statement so modified or
superseded  shall  not be  deemed,  except  as so  modified  or  superseded,  to
constitute a part of this Prospectus.

                                       2
<PAGE>

      The  Company  will  provide  without  charge  to each  person to whom this
Prospectus is delivered,  upon the request of any such person,  a copy of any or
all of the  Incorporated  Documents,  excluding the exhibits thereto unless such
exhibits  are  specifically  incorporated  by  reference  into  such  documents.
Requests for such documents should be directed to Richard C. Kelly,  Senior Vice
President,  Finance, Treasurer and Chief Financial Officer, by mail at 1225 17th
Street,  Suite  900,  Denver,  Colorado  80202-5533,  or by  telephone  at (303)
571-7511.


                                  THE COMPANY

      The Company, incorporated through merger of predecessors under the laws of
the State of Colorado in 1924, is an operating public utility engaged,  together
with its subsidiaries,  principally in the generation,  purchase,  transmission,
distribution  and  sale  of  electricity  and  in  the  purchase,  transmission,
distribution,  sale and  transportation  of  natural  gas,  with  the  Company's
principal  distribution center being the Denver metropolitan area. The Company's
executive offices are located at 1225 17th Street, Denver,  Colorado 80202-5533,
where the telephone number is (303) 571-7511.

      The  Incorporated  Documents  contain  information  with  respect  to  the
proposed mergers of two wholly-owned  subsidiaries of New Century Energies, Inc.
("New  Century"),   a  newly  formed  holding  company,  into  the  Company  and
Southwestern  Public Service Company  ("SPS"),  respectively.  As a result,  New
Century  would  become the holding  company  for the  Company  and SPS,  but the
transaction  would not affect  the  outstanding  debt of the  Company or the New
Bonds offered hereby. The transaction would result in the common shareholders of
the Company owning approximately 62% of the common equity of New Century and the
common shareholders of SPS owning  approximately 38% of the common equity of New
Century.

      The  transaction is subject to customary  closing  conditions,  including,
without limitation,  the receipt of all necessary governmental approvals and the
making of all necessary governmental filings.  Furthermore, the merger agreement
may be terminated under certain circumstances, including, without limitation, by
mutual written consent of the Boards of Directors of the Company and SPS.

      Following the transaction, New Century will maintain its corporate offices
in Denver,  Colorado and significant  operating offices in Amarillo,  Texas. The
headquarters of the Company and SPS will remain in their current locations,  and
each of the Company and SPS will continue their existing utility operations.

                                       3

<PAGE>
<TABLE>
<CAPTION>

                       RATIO OF CONSOLIDATED EARNINGS TO
                          CONSOLIDATED FIXED CHARGES

                                  Twelve Months Ended             Six Months
                                     December 31,                Ended June 30,
<S>                      <C>    <C>     <C>     <C>    <C>           <C>

                         1991   1992    1993    1994   1995          1996
                         ----   ----    ----    ----   ----          ----
Ratio of consolidated    2.94   2.43    2.54    2.53   2.78          2.95
earnings to consolidated
fixed charges
</TABLE>

                            APPLICATION OF PROCEEDS

      Except  as  may  be  otherwise  provided  in  the  applicable   Prospectus
Supplement or any supplement thereto,  the net proceeds from the sale of the New
Bonds  will be used to  refinance  matured or  maturing  debt  incurred  to fund
defueling expenses of the Company's Fort St. Vrain Nuclear  Generating  Station,
to fund the  Company's  construction  program  and for other  general  corporate
purposes.

                          DESCRIPTION OF THE NEW BONDS

      General:  The New  Bonds  will be  issued  in one or more  series as fully
registered bonds,  without coupons,  under an Indenture,  dated as of October 1,
1993 (the "Original 1993 Mortgage"),  between the Company and First Trust of New
York,  National  Association,  as successor  trustee  (together with any further
successor thereto, the "1993 Mortgage Trustee").  The Original 1993 Mortgage, as
supplemented  and  to  be  supplemented  by  various  supplemental   indentures,
including  one or more  supplemental  indentures  relating to the New Bonds,  is
hereinafter referred to as the "1993 Mortgage". The summaries under this heading
do not  purport  to be  complete  and are  subject  to, and  qualified  in their
entirety by, the detailed  provisions of the 1993  Mortgage.  Capitalized  terms
used under this heading which are not otherwise defined in this Prospectus shall
have the meanings  ascribed  thereto in the 1993 Mortgage.  Wherever  particular
provisions of the 1993  Mortgage or terms defined  therein are referred to, such
provisions  or  definitions  are  incorporated  by  reference  as a part  of the
statements  made herein and such  statements  are qualified in their entirety by
such  reference.  References  to article  and  section  numbers  herein,  unless
otherwise  indicated,  are  references  to article  and  section  numbers of the
Original 1993 Mortgage.

      The 1993 Mortgage provides that, in addition to the New Bonds,  other debt
securities  may be issued  thereunder,  without  limitation  as to the aggregate
principal  amount,  on the  basis of  Class A Bonds  (as  hereinafter  defined),
property  additions,  retired Mortgage  Securities (as hereinafter  defined) and
cash. (See "Issuance of Additional Mortgage  Securities".) The New Bonds and all
other debt securities heretofore or hereafter issued under the 1993 Mortgage are
collectively referred to herein as the "Mortgage Securities" or the "Bonds".

                                       4
<PAGE>

      Reference is made to the Prospectus  Supplement and any supplement thereto
for a description  of the following  terms of the series of New Bonds in respect
of which this  Prospectus is being  delivered:  (i) the title of such New Bonds;
(ii)  the  aggregate  principal  amount  of such  New  Bonds;  (iii)  the  price
(expressed as a percentage of principal  amount) at which such New Bonds will be
issued;  (iv) the date or dates on  which  the  principal  of such New  Bonds is
payable;  (v) the rate or rates at which such New Bonds will bear interest,  the
date or dates from  which such  interest  will  accrue,  the dates on which such
interest will be payable  ("Interest  Payment  Dates"),  and the regular  record
dates for the interest payable on such Interest Payment Dates;  (vi) the option,
if any, of the Company to redeem such New Bonds and the period or periods within
which,  or the date or dates on  which,  the  prices  at which and the terms and
conditions upon which, such New Bonds may be redeemed, in whole or in part, upon
the exercise of such  option;  (vii) the  obligation,  if any, of the Company to
redeem or  purchase  such New Bonds at the  option of the  registered  holder or
pursuant to any sinking fund or analogous  provisions  and the period or periods
within  which,  or the date or dates on which,  the price or prices at which and
the  terms  and  conditions  upon  which  such New  Bonds  will be  redeemed  or
purchased,  in  whole  or in  part,  pursuant  to such  obligation;  (viii)  the
denominations in which such New Bonds will be issuable, if other than $1,000 and
integral  multiples  thereof;  (ix)  whether  such New Bonds are to be issued in
whole or in part in book-entry  form and  represented  by one or more global New
Bonds and, if so, the identity of the depositary for such global New Bonds;  and
(x) any other terms of such New Bonds,  including with respect to any series, if
applicable,  any consents to  modifications  or waivers of covenants in the 1993
Mortgage or the 1939 Mortgage (as defined below)

      Payment of Bonds; Transfers;  Exchanges:  Except as may be provided in the
applicable Prospectus Supplement or any supplement thereto, interest, if any, on
each Bond  payable on each  Interest  Payment Date will be paid to the person in
whose  name such  Bond is  registered  (the  registered  holder of any  Mortgage
Security being hereinafter called a "Holder") as of the close of business on the
regular record date relating to such Interest Payment Date;  provided,  however,
that interest payable at maturity  (whether at stated maturity,  upon redemption
or  otherwise,  hereinafter  "Maturity")  will  be paid  to the  person  to whom
principal  is paid at  Maturity.  However,  if there has been a  default  in the
payment of interest on any Bond,  such defaulted  interest may be payable to the
Holder  of such  Bond as of the  close of  business  on a date  selected  by the
Trustee  which is not more than 30 days and not less  than 10 days  prior to the
date  proposed by the Company for payment of such  defaulted  interest or in any
other lawful manner not  inconsistent  with the  requirements  of any securities
exchange on which such Bond may be listed,  if the Trustee  deems such manner of
payment practicable. (See Section 307.)

      Unless  otherwise  specified  in a  Prospectus  Supplement  or  supplement
thereto,  the principal of and premium, if any, and interest on the Bonds due at
Maturity will be payable upon  presentation  of the Bonds at the corporate trust
office of First Trust of New York, National Association,  in New York, New York,
as Paying Agent for the Company.  The Company may change the Place of Payment on
the Bonds,  may appoint one or more  additional  Paying  Agents  (including  the
Company) and may remove any Paying Agent,  all 

                                       5
<PAGE>

at  its  discretion.  (See  Section  602  and  Article  1  of  the  Supplemental
Indenture(s) relating to the New Bonds.)

      Unless  otherwise  specified  in a  Prospectus  Supplement  or  supplement
thereto, the transfer of Bonds may be registered, and Bonds may be exchanged for
other Bonds of the same series and tranche,  of authorized  denominations and of
like tenor and aggregate  principal  amount,  at the  corporate  trust office of
First  Trust of New  York,  National  Association,  in New York,  New  York,  as
Security  Registrar  for the  Bonds.  The  Company  may  change  the  place  for
registration  of transfer and exchange of the Bonds,  and may  designate  one or
more  additional  places  for  such  registration  and  exchange,   all  at  its
discretion.  (See Section 602.) Except as otherwise  provided in the  applicable
Prospectus  Supplement or a supplement  thereto,  no service charge will be made
for any transfer or exchange of the Bonds,  but the Company may require  payment
of a sum  sufficient to cover any tax or other  governmental  charge that may be
imposed in  connection  with any  registration  of  transfer  or exchange of the
Bonds.  The  Company  will not be  required  to execute  or to  provide  for the
registration  of transfer of or the  exchange of (a) any Bond during a period of
15 days prior to giving any notice of  redemption  or (b) any Bond  selected for
redemption in whole or in part, except the unredeemed  portion of any Bond being
redeemed in part. (See Section 305.)

      Redemption:  Any terms for the  optional or  mandatory  redemption  of New
Bonds will be set forth in the  Prospectus  Supplement or a supplement  thereto.
Except as shall otherwise be provided in the applicable Prospectus Supplement or
a  supplement  thereto  with  respect to Bonds  redeemable  at the option of the
Holder,  Bonds will be redeemable  only upon notice by mail not less than 30 nor
more than 60 days prior to the date fixed for redemption,  and, if less than all
the  Bonds  of a  series,  or  any  tranche  thereof,  are to be  redeemed,  the
particular  Bonds to be  redeemed  will be  selected  by such method as shall be
provided for any particular series, or in the absence of any such provision,  by
such  method  of random  selection  as the  Security  Registrar  deems  fair and
appropriate. (See Sections 503 and 504.)

      Any notice of  redemption at the option of the Company may state that such
redemption will be conditional upon receipt by the Paying Agent or Agents, on or
prior to the date  fixed for such  redemption,  of money  sufficient  to pay the
principal of and premium,  if any, and interest,  if any, on such Bonds and that
if such  money has not been so  received,  such  notice  will be of no force and
effect and the Company  will not be required to redeem such Bonds.  (See Section
504.)

      While the Original 1993 Mortgage  contains  provisions for the maintenance
of the Mortgaged Property,  it does not contain any provisions for a maintenance
or sinking  fund and,  except as may be  provided in the  applicable  Prospectus
Supplement or a supplement  thereto,  there will be no  provisions  for any such
funds for the New Bonds.

                                       6
<PAGE>


     Security:  General.  Except  as  discussed  under  this  heading  and under
"Issuance of Additional Mortgage  Securities" below, all Mortgage Securities now
or  hereafter  issued  under the 1993  Mortgage  will be  secured,  equally  and
ratably, primarily by

            (a) an equal  principal  amount of first  mortgage bonds (which need
      not bear  interest)  issued  under the  Company's  Indenture,  dated as of
      December 1, 1939 (the "Original 1939  Mortgage"),  between the Company and
      First  Trust of New  York,  National  Association,  as  successor  trustee
      (together  with  any  further  successor   thereto,   the  "1939  Mortgage
      Trustee"),  and  delivered  to the Trustee  under the 1993  Mortgage  (the
      Original 1939 Mortgage,  as amended and  supplemented,  being  hereinafter
      called the "1939 Mortgage").  As discussed under  "DESCRIPTION OF THE 1939
      MORTGAGE--Security",  the 1939  Mortgage  constitutes,  subject to certain
      exceptions,  a first mortgage lien on substantially  all properties of the
      Company; and

            (b) the  lien  of the  1993  Mortgage  on  substantially  all of the
      Company's  properties  used  or to be used in or in  connection  with  the
      business of  generating,  purchasing,  transmitting,  distributing  and/or
      selling electric energy (the "Electric Utility  Business"),  which lien is
      junior to the lien of the 1939 Mortgage.

      As  discussed  below  under  "Class  A  Bonds",   following  a  merger  or
consolidation  of another  corporation  into the Company or the  transfer to the
Company  of  property  subject  to the  lien  of an  existing  mortgage  and the
assumption by the Company of all the  obligations  of the  mortgagor  under such
mortgage,  the Company could  deliver to the 1993 Mortgage  Trustee bonds issued
under a mortgage existing on the properties acquired in such transaction in lieu
of or in addition to bonds issued under the 1939  Mortgage.  In such event,  the
Mortgage  Securities  would be secured,  additionally,  by such bonds and by the
lien of the 1993 Mortgage on such properties, which would be junior to the liens
of such  existing  mortgage and the 1939 Mortgage on such  properties.  The 1939
Mortgage and all such other mortgages are hereinafter  collectively  referred to
as "Class A  Mortgages",  and all bonds issued  under the Class A Mortgages  and
delivered to the 1993 Mortgage Trustee are hereinafter  collectively referred to
as "Class A Bonds".  If and when no Class A  Mortgages  are in effect,  the 1993
Mortgage  will  constitute a first  mortgage lien on all property of the Company
subject  thereto,  subject to certain  Permitted Liens (as discussed below under
"Lien of the 1993  Mortgage.") As discussed below under "Class A Bonds",  at the
date of this  Prospectus  the only Class A Mortgage  is the 1939  Mortgage.  The
Company  currently  believes  that it is  possible  that,  prior  to the  Stated
Maturity  of the New  Bonds,  all  Class  A Bonds  outstanding  under  the  1939
Mortgage,  other than Class A Bonds  delivered to and held by the 1993  Mortgage
Trustee as the basis of authentication and delivery of Mortgage Securities,  may
have been paid, redeemed or otherwise retired and that,  thereupon,  the Class A
Bonds issued under the 1939 Mortgage would be surrendered for  cancellation  and
the 1939 Mortgage would be  discharged.  Upon discharge of the 1939 Mortgage and
assuming no other Class A Mortgage  exists at the time,  the 1993 Mortgage would
become a first  mortgage  lien on all property of the Company  subject  thereto,
subject to certain Permitted Liens.

                                       7
<PAGE>

      Class A Bonds.  Class A Bonds  issued as the basis for the  authentication
and  delivery  of  Mortgage  Securities  will be issued  and  delivered  to, and
registered in the name of, the 1993 Mortgage  Trustee or its nominee and will be
owned and held by the 1993 Mortgage  Trustee,  subject to the  provisions of the
1993  Mortgage,  for the  benefit  of the  Holders  of all  Mortgage  Securities
Outstanding  from time to time,  and the  Company  will have no interest in such
Class A Bonds.  Class A Bonds issued as the basis of authentication and delivery
of Mortgage Securities (a) will mature or be subject to mandatory  redemption on
the same dates, and in the same principal amounts,  as such Mortgage  Securities
and (b)  will  contain,  in  addition  to any  mandatory  redemption  provisions
applicable to all Class A Bonds  Outstanding under the related Class A Mortgage,
mandatory  redemption   provisions   correlative  to  provisions  for  mandatory
redemption  of  such  Mortgage  Securities   (pursuant  to  a  sinking  fund  or
otherwise),  or for  redemption  at the  option of the  Holder of such  Mortgage
Securities. Class A Bonds issued as the basis for authentication and delivery of
a series or tranche of Mortgage Securities (x) may, but need not, bear interest,
any such  interest to be payable at the same times as  interest on the  Mortgage
Securities  of such  series  or  tranche  and (y)  may,  but need  not,  contain
provisions  for the  redemption  thereof at the option of the Company,  any such
redemption  to be made at a  redemption  price  or  prices  not  less  than  the
principal  amount  of such  Class A Bonds.  (See  Sections  402 and 701.) To the
extent  that  Class A Bonds  issued  as the  basis  for the  authentication  and
delivery of New Bonds do not bear interest,  holders of Mortgage Securities will
not have the  benefit of the lien of the 1939  Mortgage  in respect of an amount
equal to accrued interest, if any, on such New Bonds; however, such holders will
nevertheless  have the  benefit of the lien of the 1993  Mortgage  in respect of
such amount.

      Any payment by the Company of principal of, or premium or interest on, the
Class A Bonds  held by the 1993  Mortgage  Trustee  will be  applied by the 1993
Mortgage  Trustee to the payment of any principal,  premium or interest,  as the
case may be, in respect of the Mortgage Securities which is then due and, to the
extent  of such  application,  the  obligation  of the  Company  under  the 1993
Mortgage  to make such  payment in respect of the  Mortgage  Securities  will be
deemed  satisfied  and  discharged.  If,  at the  time of any  such  payment  of
principal of Class A Bonds,  there shall be no principal  then due in respect of
the  Mortgage  Securities,  such payment in respect of the Class A Bonds will be
deemed to constitute  Funded Cash and will be held by the 1993 Mortgage  Trustee
as part of the Mortgaged Property, to be withdrawn,  used or applied as provided
in the 1993 Mortgage;  and thereafter the Mortgage Securities  authenticated and
delivered on the basis of such Class A Bonds will, to the extent of such payment
of principal, be deemed to have been authenticated and delivered on the basis of
the deposit of cash.  If, at the time of any such payment of premium or interest
on Class A Bonds,  there  shall be no premium or  interest,  as the case may be,
then due in respect of the Mortgage Securities, such payment will be remitted to
the Company at its request; provided,  however, that, if an Event of Default, as
described  below,  shall have occurred and be continuing,  such payment shall be
held as part of the  Mortgaged  Property  until such Event of Default shall have
been cured or waived.  (See  Section 702 and  "Withdrawal  of Cash"  below.) Any
payment by the  Company of  principal  of, or premium or interest  on,  Mortgage
Securities authenticated and delivered on the basis of the issuance and delivery
to the 1993 Mortgage  Trustee of Class A Bonds (other

                                       8
<PAGE>

than by  application  of the  proceeds  of a payment  in respect of such Class A
Bonds)  will,  to the extent  thereof,  be deemed to satisfy and  discharge  the
obligation of the Company,  if any, to make a payment of  principal,  premium or
interest,  as the case may be, in respect  of such  Class A Bonds  which is then
due. (See Section 702 and Article One of the  Supplemental  Indenture(s)  to the
1939 Mortgage  creating the Class A Bonds to be delivered in connection with the
issuance of the New Bonds.)

      The 1993 Mortgage Trustee may not sell,  assign or otherwise  transfer any
Class A Bonds  except  to a  successor  trustee  under the 1993  Mortgage.  (See
Section  704.) At the time any  Mortgage  Securities  of any series or  tranche,
which have been  authenticated  and delivered upon the basis of the issuance and
delivery to the 1993 Mortgage Trustee of Class A Bonds,  cease to be Outstanding
(other  than as a result of the  application  of the  proceeds of the payment or
redemption of such Class A Bonds),  the 1993 Mortgage  Trustee will surrender to
or upon the order of the  Company  an equal  principal  amount  of such  Class A
Bonds. (See Section 703.)

      At the date of this  Prospectus,  the only  Class A  Mortgage  is the 1939
Mortgage  and the only Class A Bonds  issuable  at this time are first  mortgage
bonds issuable thereunder.  The 1993 Mortgage provides that, in the event that a
corporation  which was a mortgagor under an existing mortgage has merged into or
consolidated  with the  Company,  or a  corporation  has  conveyed or  otherwise
transferred  property to the Company subject to the lien of an existing mortgage
and the  Company has assumed all the  obligations  of the  mortgagor  under such
existing mortgage,  and in either case such existing mortgage constitutes a lien
on properties of such other  corporation or on such transferred  properties,  as
the case may be, prior to the lien of the 1993 Mortgage,  such existing mortgage
may be  designated  by the  Company as an  additional  Class A  Mortgage.  Bonds
thereafter  issued  under such  additional  mortgage  would be Class A Bonds and
could  provide  the  basis  for the  authentication  and  delivery  of  Mortgage
Securities under the 1993 Mortgage. (See Section 706.) When no Class A Bonds are
Outstanding  under a Class A Mortgage  except for Class A Bonds held by the 1993
Mortgage  Trustee,   then,  at  the  request  of  the  Company  and  subject  to
satisfaction  of certain  conditions,  the 1993 Mortgage  Trustee will surrender
such Class A Bonds for  cancellation  and the related  Class A Mortgage  will be
satisfied  and  discharged,  the lien of such Class A Mortgage on the  Company's
property  will cease to exist and the priority of the lien of the 1993  Mortgage
will be increased accordingly. (See Section 707.)

      The 1993  Mortgage  contains no  restrictions  on the  issuance of Class A
Bonds in addition to Class A Bonds  issued to the 1993  Mortgage  Trustee as the
basis for the authentication and delivery of Mortgage Securities.  Class A Bonds
may  currently  be issued  under  the 1939  Mortgage  on the  basis of  property
additions,  retirements of bonds  previously  issued under the 1939 Mortgage and
cash deposited with the 1939 Mortgage  Trustee.  (See  "DESCRIPTION  OF THE 1939
MORTGAGE -- Issuance of Additional Bonds Under the 1939 Mortgage".)

                                       9
<PAGE>

      Lien of the 1993 Mortgage.  In the opinion of counsel for the Company (see
"EXPERTS")  based on  information  obtained  from  public  records  and from the
Company,  the  1993  Mortgage  constitutes  a  mortgage  lien  on  the  property
specifically  or  generally  described  or referred to therein as subject to the
lien thereof, except such property as may have been disposed of or released from
the lien thereof in accordance with the terms thereof, subject to no liens prior
to the lien of the 1993  Mortgage  other than the lien of the 1939  Mortgage (so
long as the 1939  Mortgage  remains in  effect),  the liens of any other Class A
Mortgages and Permitted Liens; and the 1993 Mortgage effectively subjects to the
lien thereof  property  (other than excepted  property)  acquired by the Company
after the date of the execution and delivery thereof to the extent,  and subject
to the qualifications, hereinafter described. So long as the 1939 Mortgage is in
effect,  the New Bonds will have the benefit of the first  mortgage  lien of the
1939  Mortgage  on such  property,  and the  benefit  of the  prior  lien of any
additional Class A Mortgage on any property  subject  thereto,  to the extent of
the  aggregate  principal  amount of Class A Bonds issued  under the  respective
Class A  Mortgages  and held by the 1993  Mortgage  Trustee  for the  benefit of
holders of First Collateral Trust Bonds, including the New Bonds. The properties
subject to the lien of the 1993 Mortgage,  whether  currently owned or hereafter
acquired,  are the Company's  properties  used or to be used in or in connection
with the Electric Utility Business  (whether or not such is the sole use of such
properties).  Properties  relating to the Company's gas and steam businesses are
not subject to the lien of the 1993 Mortgage.

      The lien of the 1993 Mortgage is subject to Permitted Liens which include,
among  other  things,  tax liens and other  governmental  charges  which are not
delinquent  or which are  being  contested  in good  faith;  certain  workmen's,
materialmen's and other liens;  certain judgment liens and attachments;  certain
easements,   leases,   reservations   or  other  rights  of  others   (including
governmental  entities) in, on, over, and/or across,  and laws,  regulations and
restrictions affecting, and defects, irregularities,  exceptions and limitations
in title to,  certain  property of the  Company;  certain  leasehold  interests;
certain rights and interests of others which relate to common ownership or joint
use of property and liens on the interests of others in such  property;  certain
non-exclusive  rights and  interests  retained  by the Company  with  respect to
property  used or to be used in or in  connection  with both the  businesses  in
which the Mortgaged Property is used and any other businesses; and certain other
liens and encumbrances. (See Granting Clauses and Section 101.)

      There are excepted from the lien of the 1993 Mortgage, among other things,
cash and securities not paid or delivered to, deposited with or held by the 1993
Mortgage Trustee under the 1993 Mortgage; contracts, leases and other agreements
of all kinds,  contract rights,  bills,  notes and other  instruments,  accounts
receivable,  claims,  governmental and other permits, allowances and franchises,
certain intellectual property rights and other intangibles;  automobiles,  other
vehicles,  movable equipment and aircraft;  all goods, stock in trade, wares and
merchandise  held  for  sale  or  lease  in the  ordinary  course  of  business;
materials,  supplies and other personal property  consumable in the operation of
the Mortgaged Property;  fuel, including nuclear fuel, whether or not consumable
in the operation of the  Mortgaged  Property;  all  furniture  and  furnishings;
computers,  machinery and telecommunication and other equipment used exclusively
for corporate administrative

                                       10
<PAGE>


or clerical purposes; coal, ore, gas, oil and other minerals and timber, and all
rights  and  interests  in any such  minerals  or  timber,  whether  or not such
minerals or timber have been mined or extracted from the land;  electric energy,
gas  (natural  or  artificial),  steam,  water  and  other  products  generated,
produced,  manufactured,   purchased  or  otherwise  acquired  by  the  Company;
leasehold  interests  held by the Company as lessee;  and all  property  that is
located outside of the State of Colorado. (See "Excepted Property".)

      Without the  consent of the  Holders,  the  Company and the 1993  Mortgage
Trustee may enter into  supplemental  indentures in order to subject to the lien
of the 1993 Mortgage additional  property,  whether or not used or to be used in
or in connection with the Electric  Utility Business  (including  property which
would  otherwise be excepted from such lien).  (See Section 1401.) Such property
would  thereupon  constitute  Property  Additions (so long as it would otherwise
qualify as Property  Additions as  described  below) and be available as a basis
for the issuance of Mortgage  Securities.  (See "Issuance of Additional Mortgage
Securities".)

      The 1993  Mortgage  contains  provisions  subjecting  to the lien  thereof
after-acquired property used or to be used in or in connection with the Electric
Utility Business, subject to the prior lien of the 1939 Mortgage (for as long as
such prior  lien is in  effect).  These  provisions  are  limited in the case of
consolidation   or  merger   (whether  or  not  the  Company  is  the  surviving
corporation) or transfer of the Mortgaged  Property as, or substantially  as, an
entirety.  In the  event of  consolidation  or  merger  or the  transfer  of the
Mortgaged  Property as or substantially  as an entirety,  the 1993 Mortgage will
not be required to be a lien upon any of the properties then owned or thereafter
acquired  by the  successor  corporation  except  properties  acquired  from the
Company in or as a result of such transaction and  improvements,  extensions and
additions to such properties and renewals,  replacements and substitutions of or
for  any  part  or  parts  of  such   properties.   (See  Article  Thirteen  and
"Consolidation,  Merger,  etc.") In  addition,  after-acquired  property  may be
subject to liens existing or placed thereon at the time of acquisition  thereof,
including,  but not limited to, purchase money liens and the lien of any Class A
Mortgage.

      The 1993  Mortgage  provides  that the 1993  Mortgage  Trustee will have a
lien,  prior to the lien on behalf of the holders of Mortgage  Securities,  upon
the  Mortgaged  Property  for the  payment of its  reasonable  compensation  and
expenses and for indemnity against certain liabilities. (See Section 1107.)

     Issuance of Additional Mortgage Securities:  The aggregate principal amount
of Mortgage  Securities which may be authenticated  and delivered under the 1993
Mortgage is unlimited.  (See Section 301.) Mortgage Securities of any series may
be  issued  from time to time on the basis  of,  and in an  aggregate  principal
amount not exceeding:

(a)  the aggregate principal amount of Class A Bonds issued and delivered to the
     1993 Mortgage Trustee;

                                       11
<PAGE>

(b)  70% of the  Cost or Fair  Value  to the  Company  (whichever  is  less)  of
     Property  Additions (as  described  below) which do not  constitute  Funded
     Property (generally,  Property Additions which have been (i) made the basis
     of the authentication and delivery of Mortgage  Securities,  the release of
     Mortgaged  Property  or cash  withdrawals;  (ii)  substituted  for  retired
     property or (iii) used as the basis of a credit  against,  or  otherwise in
     satisfaction  of, any sinking,  improvement,  maintenance,  replacement  or
     similar fund, provided that Mortgage Securities of the series or tranche to
     which such fund relates remain  Outstanding)  after certain  deductions and
     additions, primarily including adjustments to offset property retirements;

(c)  the aggregate  principal  amount of Retired  Securities  (which  consist of
     Mortgage  Securities no longer  outstanding  under the 1993 Mortgage  which
     have not been used for certain other  purposes  under the 1993 Mortgage and
     which have not been paid,  redeemed or otherwise retired by the application
     of  Funded  Cash),  but if Class A Bonds  had been  made the  basis for the
     authentication  and  delivery  of  such  Retired  Securities,  only if such
     Retired  Securities  became Retired  Securities  after the discharge of the
     related Class A Mortgage; and

(d)  an amount of cash deposited with the 1993 Mortgage Trustee.

(See Article Four.)

      In general, the issuance of Mortgage Securities is subject to the Adjusted
Net Earnings of the Company for 12  consecutive  months  within the preceding 18
months  being at least twice the Annual  Interest  Requirements  on all Mortgage
Securities at the time  outstanding,  new Mortgage  Securities then applied for,
all outstanding Class A Bonds other than Class A Bonds held by the 1993 Mortgage
Trustee  under the 1993  Mortgage,  and all  other  indebtedness  (with  certain
exceptions)  secured  by a lien prior to the lien of the 1993  Mortgage,  except
that no such net earnings  requirement  need be met if the  additional  Mortgage
Securities  to be issued are to have no Stated  Interest Rate prior to Maturity.
Adjusted Net Earnings are calculated before, among other things,  provisions for
income  taxes;   depreciation  or   amortization   of  property;   interest  and
amortization of debt discount and expense; any non-recurring charge to income or
retained earnings of whatever kind or nature (including  without  limitation the
recognition of expense due to the  non-recoverability of investment or expense),
whether  or not  recorded  as a  non-recurring  item in the  Company's  books of
account;  and any  refund of  revenues  previously  collected  or accrued by the
Company  subject to possible  refund.  The  calculation of Adjusted Net Earnings
also does not, or, in the case of losses or expense, is not required to, include
profits  or  losses  from  the  sale  or  other  disposition  of  property,   or
non-recurring  items of revenue,  income or expense of any kind or nature.  (See
Sections 103 and 401.)

      The Company is not required to satisfy the net earnings  requirement prior
to issuance of Mortgage  Securities  (i) as provided in (a) above if the Class A
Bonds issued and  delivered to the 1993  Mortgage  Trustee as the basis for such
issuance  have  been  authenticated  and  delivered  under the  related  Class A
Mortgage on the basis of retired

                                       12
<PAGE>

Class A Bonds  or (ii) as  provided  in (c)  above.  In  general,  the  interest
requirement  with respect to variable  interest  rate  indebtedness,  if any, is
determined with reference to the rate or rates in effect on the date immediately
preceding  such  determination  or  the  rate  to  be  in  effect  upon  initial
authentication.  With respect to Mortgage  Securities  of a series  subject to a
Periodic  Offering  (such as a  medium-term  note  program),  the 1993  Mortgage
Trustee will be entitled to receive a certificate evidencing compliance with the
net  earnings  requirements  only  once,  at or prior  to the time of the  first
authentication  and delivery of the  Mortgage  Securities  of such series.  (See
Article Four.)

      Property  Additions  generally  include any property which is owned by the
Company and is subject to the lien of the 1993  Mortgage  except  (with  certain
exceptions) goodwill,  going concern value rights or intangible property, or any
property the cost of acquisition or construction of which is properly chargeable
to an operating expense account of the Company. (See Section 104.)

      Unless  otherwise  provided in the applicable  Prospectus  Supplement or a
supplement  thereto,  until the 1939 Mortgage has been  discharged,  the Company
will  issue the New Bonds on the  basis of Class A Bonds  issued  under its 1939
Mortgage.

      Release  of  Property:  Unless an Event of  Default  has  occurred  and is
continuing,  the  Company  may  obtain  the  release  from  the lien of the 1993
Mortgage  of any  Funded  Property,  except  for cash held by the 1993  Mortgage
Trustee,  upon delivery to the 1993 Mortgage  Trustee of cash equal in amount to
the amount,  if any,  that the Cost of the property to be released (or, if less,
the Fair Value to the  Company  of such  property  at the time it became  Funded
Property) exceeds the aggregate of:

(a)   the  aggregate  principal  amount,  subject  to  certain  limitations,  of
      obligations  delivered to the 1993  Mortgage  Trustee which are secured by
      purchase money liens upon the property to be released;

(b)   the Cost or Fair Value to the  Company  (whichever  is less) of  certified
      Property   Additions  not  constituting   Funded  Property  after  certain
      deductions  and  additions,  primarily  including  adjustments  to  offset
      property  retirements  (except that such  adjustments  need not be made if
      such  Property  Additions  were  acquired or made within the 90-day period
      preceding the release);

(c)   an amount equal to 10/7ths of the principal amount of Mortgage  Securities
      the Company would be entitled to issue on the basis of Retired  Securities
      (with  such  entitlement  to  issue  such  principal  amount  of  Mortgage
      Securities being waived by operation of such release);

(d)   an amount equal to 10/7ths of the principal amount of Outstanding Mortgage
      Securities  delivered to the 1993  Mortgage  Trustee  (with such  Mortgage
      Securities to be canceled by the 1993 Mortgage Trustee);

                                       13
<PAGE>

(e)   an amount of cash  and/or  the  aggregate  principal  amount,  subject  to
      certain  limitations,  of obligations secured by purchase money liens upon
      the property to be released, which in either case is evidenced to the 1993
      Mortgage Trustee by a certificate of the trustee or other holder of a lien
      prior to the lien of the  1993  Mortgage  to have  been  received  by such
      trustee or such other holder in  accordance  with the  provisions  of such
      lien in consideration for the release of such property or any part thereof
      from such lien; and

(f)   any taxes and expenses  incidental  to any sale,  exchange,  dedication or
      other disposition of the property to be released.

      Property  which is not Funded  Property may generally be released from the
lien of the 1993 Mortgage without  depositing any cash or property with the 1993
Mortgage  Trustee as long as (a) the  aggregate  amount of Cost or Fair Value to
the  Company  (whichever  is  less)  of  all  Property  Additions  which  do not
constitute Funded Property (excluding the property to be released) after certain
deductions and additions,  primarily  including  adjustments to offset  property
retirements,  is not less than zero or (b) the Cost or Fair Value  (whichever is
less) of  property to be released  does not exceed the  aggregate  amount of the
Cost or Fair Value to the  Company  (whichever  is less) of  Property  Additions
acquired or made within the 90-day period preceding the release.

      The 1993  Mortgage  provides  simplified  procedures  for the  release  of
property  which has been  released  from the lien of a Class A  Mortgage,  minor
properties and property taken by eminent domain,  and provides for  dispositions
of certain  obsolete  property and grants or surrender of certain rights without
any release or consent by the 1993 Mortgage Trustee.

      If any property  released from the lien of the 1993 Mortgage  continues to
be owned by the Company after such release,  the 1993 Mortgage will not become a
lien on any  improvement,  extension  or addition to such  property or renewals,
replacements or substitutions of or for any part or parts of such property.
(See Article Eight.)

                                       14
<PAGE>

     Withdrawal  of Cash:  Unless  an  Event  of  Default  has  occurred  and is
continuing  and subject to certain  limitations,  cash held by the 1993 Mortgage
Trustee may

(a)  be withdrawn  by the Company  

     (i)  to the extent of the Cost or Fair Value to the Company  (whichever  is
          less) of Property  Additions not constituting  Funded Property,  after
          certain deductions and additions,  primarily including  adjustments to
          offset  retirements  (except that such adjustments need not be made if
          such Property Additions were acquired or made within the 90-day period
          preceding the release) or

     (ii) in an amount  equal to 10/7ths of the  aggregate  principal  amount of
          Mortgage Securities that the Company would be entitled to issue on the
          basis of Retired  Securities  (with the  entitlement  to such issuance
          being waived by operation of such withdrawal) or

     (iii)in an amount  equal to 10/7ths of the  aggregate  principal  amount of
          any  Outstanding  Mortgage  Securities  delivered to the 1993 Mortgage
          Trustee, or

 (b) upon the request of the Company, be applied to
     (i)  the purchase of Mortgage  Securities (at prices not exceeding  10/7ths
          of the principal amount thereof) or

     (ii) the payment (or provision  therefor for the satisfaction and discharge
          of any  Mortgage  Securities)  at  Stated  Maturity  of  any  Mortgage
          Securities or the  redemption (or similar  provision  therefor) of any
          Mortgage Securities which are redeemable (with any Mortgage Securities
          received by the 1993  Mortgage  Trustee  pursuant to these  provisions
          being canceled by the 1993 Mortgage Trustee) (see Section 806);

provided,  however,  that cash deposited  with the 1993 Mortgage  Trustee as the
basis for the  authentication  and delivery of Mortgage  Securities,  as well as
cash representing a payment of principal of Class A Bonds, may only be withdrawn
in an amount equal to the aggregate  principal amount of Mortgage Securities the
Company  would be entitled to issue on any basis (with the  entitlement  to such
issuance being waived by operation of such withdrawal), or may, upon the request
of the Company,  be applied to the  purchase,  redemption or payment of Mortgage
Securities at prices not  exceeding,  in the  aggregate,  the  principal  amount
thereof. (See Sections 405 and 702.)

                                       15
<PAGE>

      Consolidation, Merger, etc.: The Company may not consolidate with or merge
into any other corporation or convey,  otherwise transfer or lease the Mortgaged
Property  as or  substantially  as an  entirety  to any  Person  unless (a) such
transaction is on such terms as will fully preserve the lien and security of the
1993  Mortgage  and the rights and powers of the 1993  Mortgage  Trustee and the
Holders;  (b) the  corporation  formed by such  consolidation  or into which the
Company is merged or the Person which acquires by conveyance or other  transfer,
or which leases,  the Mortgaged Property as, or substantially as, an entirety is
a  corporation  organized  and existing  under the laws of the United  States of
America or any State or Territory thereof or the District of Columbia,  and such
corporation  executes and delivers to the 1993 Mortgage  Trustee a  supplemental
indenture  which  contains  an  assumption  by such  corporation  of the due and
punctual payment of the principal of and premium, if any, and interest,  if any,
on the Mortgage  Securities  and the  performance  of all of the  covenants  and
conditions of the Company  under the 1993  Mortgage and which  contains a grant,
conveyance, transfer and mortgage by such corporation confirming the lien of the
1993 Mortgage on the Mortgaged Property and subjecting to such lien all property
thereafter  acquired by such corporation  which shall constitute an improvement,
extension or addition to the  Mortgaged  Property or a renewal,  replacement  or
substitution  of or  for  any  part  thereof,  and,  at  the  election  of  such
corporation,  subjecting to the lien of the 1993  Mortgage  such other  property
then owned or thereafter  acquired by such corporation as such corporation shall
specify; and (c) in the case of a lease, such lease is made expressly subject to
termination  by the Company or by the 1993  Mortgage  Trustee at any time during
the continuance of an Event of Default. (See Section 1301.)

      Modification  of 1993  Mortgage:  Without the consent of any Holders,  the
Company and the 1993  Mortgage  Trustee may enter into one or more  supplemental
indentures for any of the following purposes:

(a)  to  evidence  the  succession  of  another  Person to the  Company  and the
     assumption  by any such  successor  of the  covenants of the Company in the
     1993 Mortgage and in the Mortgage Securities; or

(b)  to add one or more  covenants  of the Company or other  provisions  for the
     benefit of all  Holders or for the  benefit of the Holders of, or to remain
     in effect only so long as there shall be outstanding,  Mortgage  Securities
     of one or more specified  series,  or one or more tranches  thereof,  or to
     surrender  any  right  or power  conferred  upon  the  Company  by the 1993
     Mortgage; or

(c)  to correct or amplify the  description  of any property at any time subject
     to the lien of the 1993 Mortgage;  or to better assure,  convey and confirm
     to the 1993  Mortgage  Trustee  any  property  subject  or  required  to be
     subjected  to the lien of the 1993  Mortgage;  or to subject to the lien of
     the 1993 Mortgage  additional  property  (including property of others), to
     specify any  additional  Permitted  Liens with  respect to such  additional
     property and to modify the provisions in the 1993 Mortgage for dispositions
     of certain  types of  property  without  release  in order to  specify  any
     additional items with respect to such additional property; or

                                       16
<PAGE>

(d)  to change or eliminate any provision of the 1993 Mortgage or to add any new
     provision to the 1993 Mortgage,  provided that if such change,  elimination
     or addition  adversely affects the interests of the Holders of the Mortgage
     Securities of any series or tranche in any material  respect,  such change,
     elimination  or addition will become  effective with respect to such series
     or tranche only when no Mortgage Security of such series or tranche remains
     outstanding under the 1993 Mortgage; or

(e)  to establish the form or terms of the Mortgage  Securities of any series or
     tranche as permitted by the 1993 Mortgage; or

(f)  to provide for the  authentication  and delivery of bearer  securities  and
     coupons appertaining thereto representing interest, if any, thereon and for
     the procedures for the registration,  exchange and replacement  thereof and
     for the giving of notice to,  and the  solicitation  of the vote or consent
     of,  the  holders  thereof,  and for any and all other  matters  incidental
     thereto; or

(g)  to evidence and provide for the  acceptance of  appointment  by a successor
     trustee or by a co-trustee or separate trustee; or

(h)  to provide  for the  procedures  required  to permit  the  Company to use a
     non-certificated  system of registration  for all, or any series or tranche
     of, the Mortgage Securities; or

(i)  to change any place or places where (i) the  principal  of and premium,  if
     any, and interest, if any, on all or any series of Mortgage Securities,  or
     any tranche  thereof,  will be payable,  (ii) all or any series of Mortgage
     Securities,  or any tranche thereof, may be surrendered for registration of
     transfer,  (iii) all or any series of Mortgage  Securities,  or any tranche
     thereof, may be surrendered for exchange and (iv) notices and demands to or
     upon the Company in respect of all or any series of Mortgage Securities, or
     any tranche thereof, and the 1993 Mortgage may be served; or

(j)  to cure any ambiguity, to correct or supplement any provision therein which
     may be defective or inconsistent  with any other provision  therein,  or to
     make any other changes to the provisions thereof or to add other provisions
     with respect to matters and questions  arising under the 1993 Mortgage,  so
     long as such  other  changes  or  additions  do not  adversely  affect  the
     interests of the Holders of Mortgage Securities of any series or tranche in
     any material respect.

(See Section 1401.)

      Without  limiting the generality of the foregoing,  if the Trust Indenture
Act of 1939, as amended (the "Trust  Indenture  Act"), is amended after the date
of the Original  1993  Mortgage in such a way as to require  changes to the 1993
Mortgage  or the  incorporation  therein of  additional  provisions  or so as to
permit changes to, or the elimination of,

                                       17
<PAGE>
provisions  which,  at the date of the  Original  1993  Mortgage  or at any time
thereafter, were required by the Trust Indenture Act to be contained in the 1993
Mortgage, the 1993 Mortgage will be deemed to have been amended so as to conform
to such amendment or to effect such changes or elimination,  and the Company and
the 1993 Mortgage  Trustee may,  without the consent of any Holders,  enter into
one or more supplemental  indentures to evidence or effect such amendment.  (See
Section 1401.)

      Except as  provided  above,  the consent of the Holders of not less than a
majority in aggregate  principal amount of the Mortgage Securities of all series
then Outstanding, considered as one class, is required for the purpose of adding
any  provisions  to,  or  changing  in any  manner,  or  eliminating  any of the
provisions  of,  the  1993  Mortgage   pursuant  to  one  or  more  supplemental
indentures;  provided,  however, that if less than all of the series of Mortgage
Securities   Outstanding  are  directly  affected  by  a  proposed  supplemental
indenture,  then the  consent  only of the  Holders of a majority  in  aggregate
principal  amount of Outstanding  Mortgage  Securities of all series so directly
affected, considered as one class, will be required; and provided, further, that
if the  Mortgage  Securities  of any  series  have been  issued in more than one
tranche and if the proposed  supplemental  indenture directly affects the rights
of the  Holders of one or more,  but less than all, of such  tranches,  then the
consent only of the Holders of a majority in aggregate  principal  amount of the
Outstanding Mortgage Securities of all tranches so directly affected, considered
as one class, will be required; and provided, further, that no such amendment or
modification  may (a) change the Stated  Maturity  of the  principal  of, or any
installment of principal of or interest on, any Mortgage Security, or reduce the
principal  amount thereof or the rate of interest  thereon (or the amount of any
installment of interest thereon), or change the method of calculating such rate,
or reduce any premium payable upon the redemption  thereof, or reduce the amount
of the  principal of any Discount  Security that would be due and payable upon a
declaration  of  acceleration  of  Maturity,  or change the coin or currency (or
other  property) in which any  Mortgage  Security or any premium or the interest
thereon is payable, or impair the right to institute suit for the enforcement of
any such payment on or after the Stated  Maturity of any Mortgage  Security (or,
in the case of redemption, on or after the redemption date) without, in any such
case,  the  consent  of the  Holder of such  Mortgage  Security;  (b) permit the
creation of any lien not otherwise  permitted by the 1993 Mortgage ranking prior
to the lien of the 1993 Mortgage with respect to all or substantially all of the
Mortgaged  Property  or  terminate  the  lien  of the  1993  Mortgage  on all or
substantially  all of the  Mortgaged  Property,  or deprive  the  Holders of the
benefit of the lien of the 1993 Mortgage, without, in any such case, the consent
of the  Holders of all  Mortgage  Securities  then  Outstanding;  (c) reduce the
percentage in principal  amount of the  Outstanding  Mortgage  Securities of any
series, or any tranche thereof,  the consent of the Holders of which is required
for any such supplemental  indenture,  or the consent of the Holders of which is
required for any waiver of compliance with any provision of the 1993 Mortgage or
of any default  thereunder and its consequences,  or reduce the requirements for
quorum or voting,  without,  in any such case, the consent of the Holder of each
Outstanding  Mortgage Security of such series or tranche;  or (d) modify certain
of the  provisions of the 1993  Mortgage  relating to  supplemental  indentures,
waivers of certain  covenants  and waivers of past  defaults with respect to the
Mortgage  Securities of any series, or any tranche

                                       18
<PAGE>
thereof, without the consent of the Holder of each Outstanding Mortgage Security
of such series or tranche. A supplemental  indenture which changes or eliminates
any covenant or other  provision of the 1993 Mortgage  which has expressly  been
included  solely  for the  benefit of the  Holders  of, or which is to remain in
effect only so long as there shall be Outstanding  Mortgage Securities of one or
more specified series,  or one or more tranches thereof,  or modifies the rights
of the Holders of Mortgage Securities of such series or tranches with respect to
such covenant or other provision,  will be deemed not to affect the rights under
the 1993 Mortgage of the Holders of the Mortgage  Securities of any other series
or tranche. (See Section 1402.)

      Voting of Class A Bonds: The 1993 Mortgage provides that the 1993 Mortgage
Trustee  will,  as holder of Class A Bonds issued under the 1939 Mortgage as the
basis  for  the  issuance  of  Mortgage  Securities,  attend  such  meetings  of
bondholders  under  the  related  Class A  Mortgage,  or  deliver  its  proxy in
connection therewith,  as relate to matters with respect to which it is entitled
to vote or consent.  The 1993  Mortgage  provides  that,  so long as no Event of
Default as defined in the 1993 Mortgage has occurred and is continuing, the 1993
Mortgage  Trustee will, as holder of such Class A Bonds (a) vote in favor of the
amendments and modifications to the 1939 Mortgage  described under  "DESCRIPTION
OF THE 1939 MORTGAGE -- Voting of Class A Bonds Issued Under the 1939 Mortgage",
and (b) with respect to any amendments or  modifications to any Class A Mortgage
other than those amendments or modifications  referred to in (a), vote all Class
A Bonds Outstanding under such Class A Mortgage then held by it, or consent with
respect  thereto,  proportionately  with the vote or  consent  of holders of all
other Class A Bonds Outstanding under such Class A Mortgage the holders of which
are eligible to vote or consent, as evidenced by a certificate  delivered by the
trustee under such Class A Mortgage;  provided,  however, that the 1993 Mortgage
Trustee will not vote in favor of, or consent to, any amendment or  modification
of a Class A Mortgage which, if it were an amendment or modification of the 1993
Mortgage,  would  require  the  consent  of Holders of  Mortgage  Securities  as
described under  "Modification of the 1993 Mortgage",  without the prior consent
of Holders of Mortgage  Securities which would be required for such an amendment
or modification of the 1993 Mortgage.
(See Section 705.)

      Waiver:  The Holders of at least a majority in aggregate  principal amount
of all Mortgage  Securities  may waive the Company's  obligations to comply with
certain covenants,  including the covenants to maintain its corporate  existence
and properties,  pay taxes and discharge liens,  maintain certain  insurance and
make such recordings and filings as are necessary to protect the security of the
Holders and the rights of the 1993 Mortgage  Trustee and the covenant  described
above with  respect to merger,  consolidation  or the  transfer  or lease of the
Mortgaged  Property as, or  substantially  as, an entirety,  provided  that such
waiver  occurs before the time such  compliance  is required.  The Holders of at
least a majority  of the  aggregate  principal  amount of  Outstanding  Mortgage
Securities  of all affected  series or tranches,  considered  as one class,  may
waive,  before  the time  for  such  compliance,  compliance  with any  covenant
specified with respect to Mortgage  Securities of such series or tranches.  (See
Section 609.)

                                       19
<PAGE>
     Events of Default:  Each of the following  events  constitutes  an Event of
Default under the 1993 Mortgage:

(a)  failure to pay interest on any Mortgage  Security  within 60 days after the
     same becomes due;

(b)  failure to pay  principal of or premium,  if any, on any Mortgage  Security
     within 3 business days after the Maturity thereof;

(c)  failure to perform or breach of any  covenant  or  warranty  of the Company
     contained in the 1993 Mortgage (other than a covenant or warranty a default
     in the  performance  of which or  breach of which is dealt  with  elsewhere
     under this paragraph) for a period of 90 days after there has been given to
     the Company by the 1993  Mortgage  Trustee,  or to the Company and the 1993
     Mortgage  Trustee  by the  Holders of at least 33% in  principal  amount of
     Outstanding Mortgage  Securities,  a written notice specifying such default
     or breach and requiring it to be remedied and stating that such notice is a
     "Notice of Default", unless the 1993 Mortgage Trustee, or the 1993 Mortgage
     Trustee and the Holders of a principal  amount of Mortgage  Securities  not
     less than the principal amount of Mortgage  Securities the Holders of which
     gave such  notice,  as the case may be, agree in writing to an extension of
     such  period  prior to its  expiration;  provided,  however,  that the 1993
     Mortgage  Trustee,  or the 1993 Mortgage  Trustee and such Holders,  as the
     case may be, will be deemed to have agreed to an  extension  of such period
     if corrective  action has been  initiated by the Company within such period
     and is being diligently pursued;

(d)  certain events relating to reorganization, bankruptcy and insolvency of the
     Company or appointment of a receiver or trustee for its property; and

(e)  the  occurrence  of a matured  event of default  under any Class A Mortgage
     (other than any such matured  event of default  which is of similar kind or
     character to the Event of Default  described in (c) above and which has not
     resulted in the  acceleration of the Class A Bonds  Outstanding  under such
     Class A  Mortgage);  provided  that the waiver or cure of any such event of
     default and the rescission and annulment of the consequences  thereof shall
     constitute a waiver of the  corresponding  Event of Default  under the 1993
     Mortgage and a rescission and annulment of the consequences  thereof.  (See
     Section 1001.)

                                       20
<PAGE>
      Remedies:  If an Event of Default occurs and is continuing,  then the 1993
Mortgage  Trustee  or the  Holders of not less than 33% in  principal  amount of
Mortgage Securities then Outstanding may declare the principal amount (or if the
Mortgage  Securities  are Discount  Securities,  such  portion of the  principal
amount of such Discount  Securities as may be provided for pursuant to the terms
of the  1993  Mortgage)  of all of the  Mortgage  Securities  then  Outstanding,
together  with  premium,  if any, and accrued  interest,  if any,  thereon to be
immediately due and payable.  At any time after such declaration of acceleration
of the Mortgage  Securities then Outstanding,  but before the sale of any of the
Mortgaged  Property  and before a judgment  or decree for payment of money shall
have  been  obtained  by the  1993  Mortgage  Trustee  as  provided  in the 1993
Mortgage,  the Event or Events of Default  giving  rise to such  declaration  of
acceleration  will, without further act, be deemed to have been waived, and such
declaration and its  consequences  will,  without further act, be deemed to have
been rescinded and annulled, if

          (a) the Company has paid or deposited with the 1993 Mortgage Trustee a
      sum sufficient to pay:

             (i)   all overdue interest, if any, on all Mortgage Securities then
          Outstanding;

             (ii)  the  principal  of   and  premium,  if  any, on  any Mortgage
          Securities  then  Outstanding  which have become due otherwise than by
          such  declaration  of acceleration and interest thereon at the rate or
          rates prescribed therefor in such Mortgage Securities; and

             (iii) all amounts due to the 1993 Mortgage Trustee as compensation
          and  reimbursement as provided in the 1993 Mortgage; and

          (b) any  other Event  or Events of Default, other than the non-payment
      of the principal of Mortgage Securities which shall have become due solely
      by such  declaration of  acceleration,  shall have been cured or waived as
      provided in the 1993 Mortgage. (See Sections 1002 and 1017.)

      The 1993 Mortgage  provides that, under certain  circumstances  and to the
extent  permitted by law, if an Event of Default occurs and is  continuing,  the
1993 Mortgage Trustee has the power to take possession of, and to hold,  operate
and manage, the Mortgaged Property or, with or without entry, sell the Mortgaged
Property.  If the  Mortgaged  Property  is sold,  whether  by the 1993  Mortgage
Trustee or pursuant to judicial  proceedings,  the principal of the  Outstanding
Mortgage  Securities,  if not  previously  due,  will  become  immediately  due,
together with premium,  if any, and any accrued  interest.  (See Sections  1003,
1004 and 1005.)

      If an Event of Default occurs and is continuing, the Holders of a majority
in principal  amount of the Mortgage  Securities then  Outstanding will have the
right to direct the time, method and place of conducting any proceedings for any
remedy  available to the 1993
                                       21
<PAGE>
Mortgage Trustee or exercising any trust or power conferred on the 1993 Mortgage
Trustee, provided that (a) such direction does not conflict with any rule of law
or with the 1993  Mortgage,  and could not involve the 1993 Mortgage  Trustee in
personal  liability  in  circumstances  where  indemnity  would not, in the 1993
Mortgage  Trustee's  sole  discretion,  be  adequate  and (b) the 1993  Mortgage
Trustee may take any other action  deemed  proper by the 1993  Mortgage  Trustee
which is not inconsistent with such direction. (See Section 1016.)

      The 1993 Mortgage  provides  that no Holder of any Mortgage  Security will
have any right to institute any proceeding,  judicial or otherwise, with respect
to the 1993  Mortgage  or for the  appointment  of a  receiver  or for any other
remedy  thereunder  unless  (a) such  Holder  has  previously  given to the 1993
Mortgage  Trustee  written  notice of a  continuing  Event of  Default;  (b) the
Holders  of not less  than a  majority  in  aggregate  principal  amount  of the
Mortgage  Securities  then  Outstanding  have made  written  request to the 1993
Mortgage  Trustee to institute  proceedings  in respect of such Event of Default
and have offered the 1993 Mortgage Trustee  reasonable  indemnity  against costs
and  liabilities to be incurred in complying  with such request;  and (c) for 60
days after  receipt of such  notice,  the 1993  Mortgage  Trustee  has failed to
institute any such  proceeding and no direction  inconsistent  with such request
has been given to the 1993  Mortgage  Trustee  during such 60-day  period by the
Holders of a majority in aggregate  principal amount of Mortgage Securities then
Outstanding.  Furthermore,  no Holder  will be entitled  to  institute  any such
action if and to the extent  that such action  would  disturb or  prejudice  the
rights of other Holders. (See Section 1011.) Notwithstanding that the right of a
Holder to institute a proceeding with respect to the 1993 Mortgage is subject to
certain conditions precedent,  each Holder of a Mortgage Security has the right,
which is absolute and unconditional,  to receive payment of the principal of and
premium, if any, and interest, if any, on such Mortgage Security when due and to
institute suit for the enforcement of any such payment,  and such rights may not
be impaired  without the consent of such Holder.  (See  Section  1012.) The 1993
Mortgage  provides that the 1993 Mortgage Trustee give the Holders notice of any
default  under the 1993 Mortgage to the extent  required by the Trust  Indenture
Act,  unless such default  shall have been cured or waived,  except that no such
notice to Holders of a default of the  character  described  in clause (c) under
"Events of  Default"  may be given  until at least 75 days after the  occurrence
thereof.  For purposes of the preceding  sentence,  the term "default" means any
event which is, or after  notice or lapse of time,  or both,  would  become,  an
Event of Default.  (See Section 1102.) The Trust Indenture Act currently permits
the 1993  Mortgage  Trustee to withhold  notices of default  (except for certain
payment  defaults) if the 1993  Mortgage  Trustee in good faith  determines  the
withholding of such notice to be in the interests of the Holders.

      As a condition  precedent to certain actions by the 1993 Mortgage  Trustee
in the enforcement of the lien of the 1993 Mortgage and institution of action on
the  Mortgage  Securities,  the  1993  Mortgage  Trustee  may  require  adequate
indemnity  against costs,  expenses and liabilities to be incurred in connection
therewith. (See Sections 1011 and 1101.)

                                       22
<PAGE>
      In addition to every other right and remedy provided in the 1993 Mortgage,
the 1993 Mortgage Trustee may exercise any right or remedy available to the 1993
Mortgage  Trustee in its  capacity  as owner and  holder of Class A Bonds  which
arises as a result of a default  or matured  event of default  under any Class A
Mortgage,  whether  or not an Event of  Default  under  the  1993  Mortgage  has
occurred and is continuing. (See Section 1020.)

      Defeasance:  Any Mortgage  Security or  Securities,  or any portion of the
principal  amount thereof,  will be deemed to have been paid for purposes of the
1993 Mortgage,  and, at the Company's  election,  the entire indebtedness of the
Company in respect thereof will be deemed to have been satisfied and discharged,
if there has been  irrevocably  deposited with the 1993 Mortgage  Trustee or any
Paying Agent (other than the Company),  in trust:  (a) money  (including  Funded
Cash not  otherwise  applied  pursuant to the 1993  Mortgage) in an amount which
will be sufficient;  or (b) Eligible  Obligations (as described  below) which do
not contain provisions  permitting the redemption or other prepayment thereof at
the option of the issuer  thereof,  the  principal  of and the interest on which
when due, without any regard to reinvestment thereof, will provide monies which,
together  with the money,  if any,  deposited  with or held by the 1993 Mortgage
Trustee or such Paying Agent,  will be  sufficient;  or (c) a combination of (a)
and (b) which will be  sufficient  to pay when due the principal of and premium,
if any, and interest, if any, due and to become due on such Mortgage Security or
Securities or portions  thereof.  (See Section 901.) For this purpose,  Eligible
Obligations  include  direct  obligations  of,  or  obligations  unconditionally
guaranteed by, the United States of America  entitled to the benefit of the full
faith  and  credit  thereof,  and  certificates,  depositary  receipts  or other
instruments which evidence a direct ownership interest in such obligations or in
any specific interest or principal payments due in respect thereof.

      It  is  possible  that  for  Federal   income  tax  purposes  any  deposit
contemplated in the preceding  paragraph could be treated as a taxable  exchange
of the related Mortgage Securities for an issue of obligations of the trust or a
direct  interest  in the cash and  securities  held in the trust.  In that case,
Holders of such Mortgage Securities would recognize gain or loss as if the trust
obligations  or the  cash or  securities  deposited,  as the  case  may be,  had
actually been received by them in exchange for their Mortgage  Securities.  Such
gain or loss,  generally,  would be capital  in nature to  Holders  for whom the
Mortgage  Securities  are held as capital  assets and any  deductions for losses
would be  subject to  certain  limitations.  Such  Holders  thereafter  would be
required to include in income a share of the  income,  gain or loss of the trust
or the income from the securities  held in trust, as the case may be. The amount
so required to be included  in income  could be  different  from the amount that
would be includible in the absence of such  deposit.  Prospective  investors are
urged to consult their own tax advisors as to the specific  consequences to them
of such deposit.
  
                                     23
<PAGE>

      Resignation of the 1993 Mortgage  Trustee:  The 1993 Mortgage  Trustee may
resign at any time by giving  written  notice  thereof to the  Company or may be
removed at any time by Act of the Holders of a majority in  principal  amount of
Mortgage Securities then Outstanding  delivered to the 1993 Mortgage Trustee and
the  Company.  No  resignation  or removal of the 1993  Mortgage  Trustee and no
appointment of a successor trustee will become effective until the acceptance of
appointment by a successor  trustee in accordance  with the  requirements of the
1993  Mortgage.  So long as no Event of Default or event which,  after notice or
lapse of time,  or both,  would  become an Event of Default has  occurred and is
continuing,  if the  Company  has  delivered  to the  1993  Mortgage  Trustee  a
resolution  of its Board of Directors  appointing  a successor  trustee and such
successor has accepted such appointment in accordance with the terms of the 1993
Mortgage,  the 1993  Mortgage  Trustee  will be deemed to have  resigned and the
successor  will be deemed to have been  appointed as trustee in accordance  with
the 1993 Mortgage. (See Section 1110.)

      Evidence to be Furnished to the 1993  Mortgage  Trustee:  Compliance  with
1993 Mortgage  provisions is evidenced by written statements of Company officers
or persons  selected  or paid by the  Company.  In certain  cases,  opinions  of
counsel and certification of an engineer, accountant,  appraiser or other expert
(who in some cases must be independent) must be furnished. In addition, the 1993
Mortgage  requires  that the Company give the 1993  Mortgage  Trustee,  not less
often than annually,  a brief statement as to the Company's  compliance with the
conditions and covenants under the 1993 Mortgage.

      Concerning  the  1993  Mortgage  Trustee:  The  Company  conducts  banking
transactions  with affiliates of the 1993 Mortgage  Trustee in the normal course
of the Company's  business and uses the 1993 Mortgage  Trustee or its affiliates
as trustee for various debt issues.

                        DESCRIPTION OF THE 1939 MORTGAGE

      General:  The  summaries  under this heading do not purport to be complete
and are subject to the detailed provisions of the 1939 Mortgage, a copy of which
is filed as an exhibit to the Registration Statement of which this Prospectus is
a part.  Capitalized  terms  used  under this  heading  which are not  otherwise
defined in this Prospectus shall have the meanings  ascribed thereto in the 1939
Mortgage.  Wherever particular  provisions or terms defined therein are referred
to, such provisions or definitions are  incorporated by reference as part of the
statements  made herein and such  statements  are qualified in their entirety by
such  reference.  References  to article  and  section  numbers  herein,  unless
otherwise  indicated,  are  references  to articles  and section  numbers of the
Original 1939 Mortgage.

                                       24
<PAGE>

      Security.  Class A Bonds  issued  under the 1939  Mortgage  will rank pari
passu,  except as to any sinking fund or similar fund  provided for a particular
series,  with all bonds at any time outstanding under the 1939 Mortgage.  In the
opinion  of  counsel  for  the  Company  (see  "EXPERTS"),   the  1939  Mortgage
constitutes  a first  mortgage  lien on the property  specifically  or generally
described  therein as subject to the lien  thereof,  except such property as may
have been disposed of or released  from the lien thereof in accordance  with the
terms thereof,  subject to no liens prior to the lien of the 1939 Mortgage other
than Permitted  Encumbrances,  as defined therein;  and the 1939 Mortgage by its
terms effectively  subjects to the lien thereof all property (except property of
the kinds  specifically  excepted from the lien thereof) acquired by the Company
after the date of the  execution  and  delivery  thereof,  subject to  Permitted
Encumbrances, to any lien thereon existing, and to any liens for unpaid portions
of the purchase money placed thereon, at the time of such acquisition,  and also
subject to certain  limitations in the case of consolidation,  merger or sale of
substantially all the mortgaged  property.  The principal  properties subject to
the lien of the 1939 Mortgage are the electric and gas  properties  owned by the
Company and  securities  of certain  subsidiaries.  (See  Granting  and Habendum
Clauses,  Sections 2 and 3 of Article I, and Section 3 of Article XI of the 1939
Mortgage.)

      The 1939 Mortgage  provides  that the 1939  Mortgage  Trustee shall have a
lien  prior  to  the  bonds  on  the  mortgaged  property  for  payment  of  its
compensation,  expenses and  disbursements  and for  indemnity  against  certain
liabilities. (See Section 10 of Article XII of the 1939 Mortgage.)

      Issuance of Additional Bonds Under the 1939 Mortgage. Additional bonds may
be issued under the 1939 Mortgage in a principal  amount equal to (a) 60% of net
property  additions (as defined in the 1939  Mortgage)  acquired or  constructed
within  five  years of  certification  to the  1939  Mortgage  Trustee,  (b) the
principal  amount of certain  retired bonds or prior lien bonds or (c) deposited
cash (in certain cases 60% thereof).
See "Voting of Class A Bonds Issued Under the 1939 Mortgage".

      No bonds may be issued under the 1939 Mortgage, as provided in clauses (a)
and (c) above,  unless the net  earnings of the Company (as defined in Section 5
of Article I of the 1939  Mortgage  and as  discussed  below) are at least 2-1/2
times the annual  interest on all bonds  issued and  outstanding  under the 1939
Mortgage,  including the bonds applied for (but  excluding any bonds to be paid,
retired  or  redeemed  with  the  proceeds  of  the  bonds  applied  for),   and
indebtedness  secured by prior liens.  Such net earnings test generally need not
be  satisfied  prior to the  issuance  of bonds as  provided in clause (b) above
unless  (x) the new bonds are  issued  more than two years  prior to the  stated
maturity of the retired  bonds and the new bonds bear a greater rate of interest
than the  retired  bonds or (y) the new bonds are  issued in  respect of retired
bonds,  the interest  charges on which have been  excluded from any net earnings
certificate  filed with the 1939 Mortgage  Trustee since the  retirement of such
bonds.  (See  Article  III of the 1939  Mortgage.)  See "Voting of Class A Bonds
Issued Under the 1939 Mortgage".

                                       25
<PAGE>

      Cash  deposited  under clause (c) above may be withdrawn by the Company in
an amount equal to the principal  amounts of bonds issuable  pursuant to clauses
(a) and (b) above (in certain cases 166-2/3% thereof) without regard to earnings
or may be applied to the purchase or  redemption  of bonds of one or more series
selected by the  Company.  (See  Sections 8, 9 and 10 of Article III of the 1939
Mortgage.) See "Voting of Class A Bonds Issued Under the 1939 Mortgage".

      Net  earnings  are  computed  before   provision  for   depreciation   and
amortization  of  property,  income and  profits  taxes (as  defined in the 1939
Mortgage),  interest on any  indebtedness  and amortization of debt discount and
expense  and do not take into  account  any  profits or losses  from the sale or
disposal of capital  assets or  securities.  (See  Section 5 of Article I of the
1939 Mortgage.)

      Property  additions  under the 1939  Mortgage  consist of property used or
useful in the electric, gas or steam business (with certain exceptions) acquired
or constructed by the Company within five years next preceding the certification
thereof to the 1939  Mortgage  Trustee.  (See Section 4 of Article I of the 1939
Mortgage.) See "Voting of Class A Bonds Issued Under the 1939 Mortgage".

      The approximate amount of net property additions as of March 31, 1996, and
the amount of retired bonds as of September  30, 1996,  available for use as the
basis for the issuance of Class A Bonds under the 1939 Mortgage,  subject to the
net earnings  restrictions  discussed above, were $373,263,821 and $968,180,000,
respectively.  The Company will determine, at the time of each issuance of Class
A Bonds under the 1939  Mortgage  which are to be the basis for the  issuance of
New Bonds,  whether such Class A Bonds will be issued upon the basis of property
additions  or  retired  bonds.  As of  September  30,  1996,  $1,144,917,000  in
aggregate  principal amount of bonds were  outstanding  under the 1939 Mortgage,
$472,167,000 aggregate  principal amount of which was held by the 1993  Mortgage
Trustee as security for outstanding Mortgage Securities under the 1993 Mortgage.

      The 1939 Mortgage contains restrictions on (a) the acquisition of property
securing  prior  lien  indebtedness  in excess  of 60% of the fair  value of the
property  and (b) the  issuance  of  bonds,  withdrawal  of cash or  release  of
property on the basis of property subject to prior lien. Prior lien indebtedness
secured  by  property  theretofore  acquired  may not be  increased  unless  the
evidence  thereof is pledged with the 1939 Mortgage  Trustee.  (See Section 4 of
Article I and  Sections 15, 17 and 19 of Article IV of the 1939  Mortgage.)  See
"Voting of Class A Bonds Issued Under the 1939 Mortgage".

                                       26
<PAGE>

      Maintenance  and  Replacement  Fund for Bonds  Outstanding  Under the 1939
Mortgage:  Although there will be no provision for a maintenance and replacement
fund with respect to Class A Bonds  issued under the 1939  Mortgage as the basis
for the  issuance  of New Bonds,  the Company has  covenanted,  with  respect to
various  series of  outstanding  bonds issued under the 1939  Mortgage  maturing
through  July  1,  1998,  that,  so long as any  bond  of  such  series  remains
outstanding,  the  Company  will,  for each  calendar  year  (herein  called the
"accounting  period"),  pay to the 1939 Mortgage  Trustee,  as a Maintenance and
Replacement  fund,  an  amount in cash not less than the sum of 15% of the gross
electric  operating  revenues  and  10% of the  gross  gas and  steam  operating
revenues (as defined in the 1939 Mortgage,  which, among other things,  provides
for the deduction  therefrom of the cost of purchased electric current,  gas and
steam) derived from the mortgaged property during the accounting  period,  less,
however,  the following optional credits: (a) expenditures during the accounting
period for repairs and  maintenance of the mortgaged  property;  (b) the cost of
property  additions  during  the  accounting  period  deemed to renew or replace
retired or abandoned  property,  subject to adjustment for any outstanding prior
lien bonds secured by such property  additions;  (c) the principal amount of all
bonds and/or 166-2/3% of the principal  amount of all prior lien bonds,  retired
or  redeemed  and for which no bonds  have  been  issued,  credit  taken or cash
withdrawn under the 1939 Mortgage;  and (d) net property additions to the extent
of 100% thereof.  Cash so deposited may be applied to the purchase or redemption
of such bonds as the Company may designate,  which by their terms are redeemable
prior to  maturity  (including  any of the Class A Bonds  issued  under the 1939
Mortgage  that are so  redeemable  and that  were  issued  as the  basis for the
issuance of Bonds) at a price not exceeding the then current redemption price as
set forth in the relevant  supplemental  indenture  and the accrued  interest on
such bonds, or may be withdrawn upon the basis of certain property  additions or
certain  retired bonds or prior lien bonds.  (See Section 8 of Article IV of the
1939 Mortgage and Article Two of certain  supplemental  indentures.) See "Voting
of Class A Bonds Issued Under the 1939 Mortgage".

      The series of outstanding bonds which contain  maintenance and replacement
fund  covenants  mature through July 1, 1998, but may be redeemed prior to their
stated maturity.  The Company does not anticipate  issuing any additional series
of bonds under the 1939 Mortgage which will contain such covenants.  The Company
will no longer  be bound by such  covenants  after all the bonds of such  series
have been retired.

                                       27
<PAGE>

      Modification  of the 1939  Mortgage:  The 1939  Mortgage and the rights of
bondholders  thereunder may be modified with the consent of the Company,  and of
the 1939 Mortgage Trustee if deemed affected,  and the consent of the holders of
not less than 75% in principal amount of the bonds then  outstanding,  or of not
less than 75% in principal  amount of the  outstanding  bonds of any one or more
series  which  may be  affected  by  any  such  modification;  except  that  the
bondholders,  without the consent of the holder of each bond  affected,  have no
power to (a) extend the time of payment of the  principal  of or interest on any
bonds; (b) reduce the principal amount thereof or the rate of interest  thereon,
or otherwise  modify the terms of payment of  principal or interest;  (c) permit
the  creation of any lien  ranking  prior to or on a parity with the lien of the
1939  Mortgage with respect to any of the  mortgaged  property;  (d) deprive any
nonassenting  bondholder of a lien upon the mortgaged  property for the security
of his/her bonds; or (e) reduce the percentage of bondholders authorized to take
such action.  (See Article XIV of the 1939  Mortgage.)  The Company has reserved
the right to amend the 1939  Mortgage  without  any  consent or other  action by
holders of any series of bonds created after October 31, 1975 (including Class A
Bonds issued under the 1939 Mortgage as the basis for the issuance of New Bonds)
to reduce the required  consent of bondholders  described above from 75% to 60%.
(See Article Five of the Supplemental Indenture dated as of November 1, 1977.)

      Voting of Class A Bonds Issued Under the 1939 Mortgage:  The 1993 Mortgage
provides  that,  so long as no Event of Default as defined in the 1993  Mortgage
has occurred and is continuing  thereunder,  the 1993 Mortgage  Trustee will, as
holder of Class A Bonds  issued  under the 1939  Mortgage  and  delivered as the
basis for the issuance of Bonds,

            (a) vote or consent in favor of amendments or  modifications  to the
      1939 Mortgage of substantially the same tenor and effect as follows:

                   (i)  to  expand  the  definition  of  property  additions  to
            eliminate geographical  restrictions to certain states and allow the
            inclusion  of  properties  located  anywhere  in the United  States,
            Canada  and  Mexico,  or their  coastal  waters;  to  include  space
            satellites and stations,  solar power satellites and other analogous
            facilities;  to include nuclear fuel and other analogous  devices or
            substances  and to establish  other  provisions  as to such fuel; to
            include  properties  located  on leased  real  property,  subject to
            certain limitations; to include goodwill when acquired with a public
            utility system,  subject to certain  limitations;  and to delete the
            requirement   that   property   additions   have  been  acquired  or
            constructed within five years;

                  (ii)  to remove the requirement that certificates delivered to
            the 1939 Mortgage Trustee be verified;

                  (iii) to   liberalize  the  requirements  for  publication  of
            notices of redemption and other notices;

                                       28
<PAGE>

                  (iv)  to eliminate the maintenance and replacement fund or, in
            the alternative,

                        (A) to change the amount of cash deliverable to the 1939
                  Mortgage  Trustee  to the  lower  of (x)  10% of the  combined
                  electric,  gas  and  steam  gross  operating  revenues  of the
                  Company or (y) 2% of the cost of the  depreciable  property of
                  the Company,  less the accumulated provision for depreciation;
                  and

                        (B) to change the definition of gross operating revenues
                  to deduct the cost of fuel used to provide  electric,  gas and
                  steam services;

                   (v) to change the opinion of counsel required to be delivered
            upon  the   certification  of  property   additions  to  delete  the
            requirement  that the Company  have all  necessary  permission  from
            governmental authorities to use and operate such property additions;

                  (vi) to specifically allow the inclusion of earnings collected
            subject  to refund in net  earnings  for  purposes  of the  interest
            coverage requirement for the issuance of bonds;

                  (vii) to specifically  permit the debt component,  in addition
            to the equity  component,  of the  allowance  for funds used  during
            construction  to be included  in net  earnings  for  purposes of the
            interest coverage requirement for the issuance of bonds;

                  (viii)(A) to reduce the interest coverage  requirement for the
                        issuance  of bonds to 2 times  from 2-1/2  times  annual
                        interest charges on outstanding  bonds,  including bonds
                        applied  for,  and prior lien  indebtedness;  or, in the
                        alternative,

                        (B) to change such coverage requirement to a requirement
                        that net  earnings be at least equal to either (x) 2 (or
                        any higher amount) times annual interest  charges on, or
                        (y) 15%  (or any  higher  percentage)  of the  aggregate
                        principal amount of,  outstanding  bonds,  including the
                        bonds applied for, and prior lien indebtedness;

                  (ix) to remove the restrictions on acquiring  property subject
            to a prior lien (retaining,  however, the restrictions on certifying
            such property as property additions);

                   (x) to raise  the  minimum  dollar  amount  of fire and other
            losses  that  must be  payable  to the 1939  Mortgage  Trustee  from
            $50,000 to 3% (or any higher  percentage) of the principal amount of
            outstanding  bonds; and to

                                       29
<PAGE>

            specifically  permit  the  Company  to carry insurance policies with
            deductible  provisions  equal  to  3% (or any higher  percentage) of
            the  principal   amount   of   outstanding   bonds  or   any  higher
            deductible  amount  usually  contained  in  the  policies  of  other
            companies owning and operating similar properties;

                  (xi)  to  delete  the  covenant  of the  Company  to  "observe
            and  conform to all valid requirements of any governmental authority
            relative to any of the mortgaged property";

                  (xii) to delete the requirement that the 1939 Mortgage Trustee
            be located in New York,  New York and that the  Company  maintain an
            office in New York, New York, to make payments on bonds and register
            transfers thereof;

                  (xiii) to modify the  special  release  provision  of the 1939
            Mortgage to increase the amount of the  aggregate  value of property
            which may be released from the lien of the 1939 Mortgage  within any
            period of 12 consecutive calendar months without compliance with all
            the conditions of the general release  provision from $25,000 to (A)
            the greater of $25,000 or 1% of the  aggregate  principal  amount of
            outstanding  bonds or (B) the  greater of  $10,000,000  or 3% of the
            aggregate principal amount of outstanding bonds (or any lower amount
            or percentage);

                  (xiv) to permit bonds to be issued under the 1939  Mortgage in
            a principal amount equal to 70% of net property additions instead of
            60% and to make correlative changes in provisions relating to, among
            other  things,  the  release of  property  from the lien of the 1939
            Mortgage,  the withdrawal of cash held by the 1939 Mortgage Trustee,
            the acquisition and use under the 1939 Mortgage of property securing
            prior lien  indebtedness,  and the use of retired  prior lien bonds;
            and

                  (xv) to modify the  definition of all defaults  under the 1939
            Mortgage  to be  substantially  identical  to the  Events of Default
            under the 1993 Mortgage; and

            (b) with  respect to any  amendments  or  modifications  to the 1939
      Mortgage other than those referred to in (a) above, vote all Class A Bonds
      Outstanding  under the 1939  Mortgage  then held by it,  or  consent  with
      respect thereto,  in the manner as described under "DESCRIPTION OF THE NEW
      BONDS -- Voting of Class A Bonds". (See Section 705 of the 1993 Mortgage.)

      The Company has reserved the right to make any or all of the modifications
to the 1939  Mortgage  described in (a)(i)  through  (a)(xiii)(A)  above without
consent or other  action of the holders of certain  outstanding  series of bonds
previously  issued  under the 1939  Mortgage  (not  including  the Class A Bonds
issued  thereunder  as  the  basis  of the issuance of

                                       30
<PAGE>

Mortgage Securities) aggregating  $433,500,000 in principal amount. (See Article
Three of the  Supplemental  Indenture dated as of March 1, 1980 and Article Four
of the Supplemental  Indentures dated as of July 1, 1990,  December 1, 1990, and
March 1, 1992, respectively.)

      The  indentures  under which certain  pollution  control  revenue bonds of
Morgan County,  Colorado and Adams County, Colorado were issued provide that the
trustees thereunder, as holders of bonds issued under the 1939 Mortgage having a
principal  amount of $156,750,000  in the aggregate,  shall vote in favor of, or
consent with respect to, any or all of the possible  modifications  described in
(a)(i) through (a)(xiii)(A) above.

      Default  Under  the 1939  Mortgage:  An event of  default  under  the 1939
Mortgage  includes a failure to pay  interest  on any bond,  or to pay a sinking
fund  installment,  for 60 days after such payment becomes due, a failure to pay
the  principal  of or premium,  if any, on any bond when the same becomes due, a
default  with  respect to the payment of  principal  of or interest on any prior
lien bonds,  a failure to perform any other covenant in the 1939 Mortgage for 90
days after  notice given to the Company by the 1939  Mortgage  Trustee or by the
holders of 10% in  principal  amount of  outstanding  bonds,  certain  events in
bankruptcy,  and an Event of  Default  under the 1993  Mortgage  and/or  certain
matured  events of default  under any other Class A Mortgage.  (See Section 1 of
Article VIII of the 1939 Mortgage and Article Five of the Supplemental Indenture
dated as of November  1, 1993  creating  the First  Mortgage  Bonds,  Collateral
Series A.) The 1939  Mortgage  Trustee may  withhold  notice of default  (except
default in the payment of  principal  of or premium,  if any, or interest on the
bonds or in the payment of a sinking fund  installment)  if it  determines  such
withholding to be in the interests of the bondholders. (See Section 2 of Article
VIII of the 1939  Mortgage.)  The Company is required to report  annually to the
1939 Mortgage Trustee as to compliance with the covenants  contained in the 1939
Mortgage. (See Section 24 of Article IV of the 1939 Mortgage.)

      Upon  the  occurrence  of a  default  under  the 1939  Mortgage,  the 1939
Mortgage Trustee or the holders of 25% in principal amount of outstanding  bonds
may declare the principal of and interest  accrued on all outstanding  bonds due
and payable immediately; provided, however, that if such default has been cured,
(a) the holders of a majority in principal amount of outstanding bonds may annul
such  declaration  or (b) if,  in making  such  declaration,  the 1939  Mortgage
Trustee shall have acted  without a direction  from the holders of a majority in
principal  amount of outstanding  bonds, or if such  declaration was made by the
holders of 25% in  principal  amount of  outstanding  bonds and the holders of a
majority in principal  amount of  outstanding  bonds shall not have  theretofore
delivered a written  notice to the contrary,  then such  declaration  shall ipso
facto be deemed to be  annulled.  (See  Section  1 of  Article  VIII of the 1939
Mortgage.)

                                       31
<PAGE>

      Action by 1939 Mortgage Trustee:  Except as otherwise provided in the 1939
Mortgage,  the holders of a majority in  principal  amount of bonds  outstanding
under the 1939 Mortgage  have the right to require the 1939 Mortgage  Trustee to
enforce the lien of the 1939  Mortgage and direct the time,  method and place of
conducting any proceedings for any remedy available to the 1939 Mortgage Trustee
under the 1939 Mortgage.  (See Section 15 of Article VIII of the 1939 Mortgage.)
No holder of bonds  outstanding under the 1939 Mortgage has the right to enforce
the lien of the 1939  Mortgage  without  giving  to the  1939  Mortgage  Trustee
written  notice of default  and unless the  holders of a majority  in  principal
amount of outstanding  bonds shall have  requested the 1939 Mortgage  Trustee to
act  and  have  offered  the  1939  Mortgage   Trustee  security  and  indemnity
satisfactory  to it against the costs,  expenses and  liabilities to be incurred
thereby and the 1939 Mortgage Trustee shall have failed to take action within 60
days. (See Section 16 of Article VIII of the 1939 Mortgage.)

      Concerning  the  1939  Mortgage  Trustee:  The  Company  conducts  banking
transactions  with affiliates of the 1939 Mortgage  Trustee in the normal course
of the Company's  business and uses the 1939 Mortgage  Trustee or its affiliates
as trustee for various debt issues.

                                LEGAL OPINIONS

      The  validity  of the New Bonds  will be passed  upon for the  Company  by
LeBoeuf,  Lamb,  Greene,  &  MacRae,  L.L.P.,  a limited  liability  partnership
including professional corporations, Denver, Colorado and New York, New York and
for any underwriters, agents or dealers by Brown & Wood LLP, New York, New York.
All legal  matters  pertaining  to titles and the  respective  liens of the 1993
Mortgage  and the 1939  Mortgage  will be  passed  upon only by  LeBoeuf,  Lamb,
Greene, & MacRae, L.L.P. In giving its opinion,  Brown & Wood LLP may rely as to
all matters of Colorado law upon the opinion of LeBoeuf, Lamb, Greene, & MacRae,
L.L.P.

                                    EXPERTS

      Reference  is made to the  Incorporated  Documents  for  specification  of
certain  information  incorporated  herein by  reference  upon the  authority of
experts.  In addition,  the statements  made in "DESCRIPTION OF THE NEW BONDS --
Security" and "DESCRIPTION OF THE 1939 MORTGAGE",  insofar as they are, or refer
to,  statements of law or legal  conclusions,  have been prepared or reviewed by
LeBoeuf,  Lamb,  Greene,  &  MacRae,  L.L.P.,  a limited  liability  partnership
including professional corporations,  counsel for the Company, and have been set
forth herein on the authority of said firm as experts.

                             PLAN OF DISTRIBUTION

      The  Company may sell each type and series of New Bonds as  applicable  in
any of three ways: (i) directly to a limited number of institutional  purchasers
or to a single purchaser,  (ii) through agents or (iii) through  underwriters or
dealers. The Prospectus

                                       32
<PAGE>

Supplement  relating to each series of New Bonds will set forth the terms of the
offering  of such New  Bonds,  including  the name or names of any such  agents,
underwriters  or  dealers;  the  purchase  price of such New  Bonds  and the net
proceeds to the Company from such sale;  any  underwriting  discounts  and other
items  constituting  underwriters'  compensation;  the initial  public  offering
price; and any discounts or concessions allowed or reallowed or paid to dealers.
Any initial public  offering  price and any discounts or concessions  allowed or
reallowed or paid to dealers may be changed from time to time.

      If  underwriters  are used in any sale of a series of New Bonds,  such New
Bonds will be  acquired  by such  underwriters  for their own account and may be
resold  from  time to time in one or  more  transactions,  including  negotiated
transactions,  at a fixed public offering price or at varying prices  determined
at the time of sale.  Unless  otherwise set forth in the  Prospectus  Supplement
relating  to a series  of New  Bonds,  the  obligations  of any  underwriter  or
underwriters  to purchase  such New Bonds will be subject to certain  conditions
precedent and such underwriter or underwriters will be obligated to purchase all
of such New Bonds if any are purchased,  except that, in certain cases involving
a default  by one or more  underwriters,  less than all of such New Bonds may be
purchased.

      If an agent of the  Company  is used in any sale of a series of New Bonds,
any  commission  payable  by the  Company to such agent will be set forth in the
Prospectus  Supplement  relating to such series of New Bonds.  Unless  otherwise
indicated in the Prospectus Supplement,  any such agent will be acting on a best
efforts basis for the period of its appointment.

      Any underwriters,  dealers or agents  participating in the distribution of
the New Bonds may be deemed to be underwriters,  and any discount or commissions
received  by them  on the  sale or  resale  of New  Bonds  may be  deemed  to be
underwriting  discounts and  commissions,  under the  Securities Act of 1933, as
amended (the "1933 Act"). Agents, underwriters and dealers may be entitled under
agreements  entered  into with the  Company to  indemnification  by the  Company
against certain liabilities, including liabilities under the 1933 Act.


                                      33

<PAGE>


- ------------------------------------    ----------------------------------------


   No dealer, salesperson or other
individual has been  authorized to
give  any  information  or to make
any  representations   other  than
contained  or incorporated by ref-
erence in  this Prospectus Supple-
ment,   the   applicable   Pricing
Supplement  or  the  Prospectus in                    $250,000,000
connection with  the offer made by
this  Prospectus  Supplement,  the
applicable  Pricing Supplement and
the  Prospectus  and,  if given or
made,  such  information or repre-                        LOGO
sentations must not be relied upon
as  having been authorized by  the
Company  or  the  Agents.  Neither
the  delivery of  this  Prospectus
Supplement, the applicable Pricing               PUBLIC SERVICE COMPANY
Supplement or  the  Prospectus nor                     OF COLORADO
any sale made hereunder and there-
under shall under any circumstance
create  an implication  that there
has  not  been  any  change in the 
affairs of the  Company since  the
date hereof. This Prospectus Supp-
lement,  the  applicable   Pricing
Supplement  and the  Prospectus do
not constitute an offer or solici-
tation  by  anyone  in  any juris-
diction  in  which  such  offer or
solicitation  is not authorized or
in  which  the person  making such
offer is not qualified to do so or
to  anyone  to whom it is unlawful
to make such offer or solicitation.        Secured Medium-Term Notes, Series B
                                          Due From Nine Months To Thirty Years
         ---------------                            From Date of Issue

        TABLE OF CONTENTS

                               Page

      Prospectus Supplement                        ----------------
                                                PROSPECTUS SUPPLEMENT
Supplemental Description of                        ----------------
 the Notes....................  S-2
Plan of Distribution..........  S-8

           Prospectus

Available Information.........    2
Incorporation of Certain
 Documents By Reference.......    2               Merrill Lynch & Co.
The Company...................    3               Goldman, Sachs & Co.
Ratio of Consolidated Earnings
 to Consolidated Fixed Charges.   4
Application of Proceeds........   4
Description of the New Bonds...   4
Description of the 1939 Mortgage.24
Legal Opinions................   32                   _______, 1996
Experts.......................   32
Plan of Distribution..........   32


- ------------------------------------    ----------------------------------------



<PAGE>


                                    PART II

                    INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.    Other Expenses of Issuance and Distribution.

    SEC registration fee.............................................. $121,213
*   Accountants' fees and expenses ...................................   14,000
*   Company counsel's fees and expenses ..............................   60,000
*   Trustee's fees and expenses, including counsel
      and authentication fees.........................................   35,000
*   Printing expenses.................................................   20,000
*   Rating agencies' fees ............................................   60,000
*   Blue Sky fees and expenses........................................   11,000
*   Miscellaneous expenses............................................  100,000
                                                                        -------
*   Total expenses.................................................... $421,213


- ------------
*Estimated

Item 15.  Indemnification of Directors and Officers.

            Sections  7-108-402,  7-109-102,  7-109-103,  7-109-104,  7-109-105,
7-109-106,   7-109-107,   7-109-108  and  7-109-109  of  the  Colorado  Business
Corporation Act provide for indemnification of directors,  officers,  employees,
fiduciaries and agents of Colorado corporations such as the Registrant,  subject
to certain limitations, and authorize such corporations to purchase and maintain
insurance on behalf of such persons  against any liability  incurred in any such
capacity or arising out of their status as such.  The  Registrant  currently has
such insurance in effect.

            A resolution  adopted at a special  meeting of  stockholders  of the
Registrant held in November,  1943, provides: "That each Director and Officer of
the Company (or his legal  representative)  shall be  indemnified by the Company
against all claims,  liabilities,  expenses and costs imposed upon or reasonably
incurred  by him in  connection  with any  action,  suit or  proceeding,  or the
settlement  or  compromise  of  any  such  claim,  liability,  action,  suit  or
proceeding  (other than amounts paid to the Company itself),  in which he may be
involved by reason of his being or having  been such  Director or Officer of the
Company,  except in relation to matters as to which he shall be finally adjudged
in any such action,  suit or proceeding to have been derelict in the performance
of his duties as such Director or Officer, provided,  however, in respect of any
such settlement or compromise that it shall have been determined,  by a majority
of the  Directors  of the  Company  not  affected  by self  interest,  that such
settlement or compromise  should be made,  and that such Director or Officer had
not been  derelict in the  performance  of his  official  duties;  and  provided
further that the  foregoing  indemnity  shall not extend to or cover any claims,
liabilities, action, suit or proceeding under the Securities Act of 1933, or any
costs or expenses in connection  therewith unless the Director or Officer of the
Company involved shall be finally adjudged in such action, suit or proceeding to
have been subject to no liability  under said Act, or in case of

                                      II-1
<PAGE>

settlement or  compromise,  unless the Company shall have obtained an opinion of
independent  counsel to the effect  that he is not  liable  under said Act.  The
foregoing right of indemnification  shall not be exclusive of any other right or
rights to which such Director or Officer may be entitled as a matter of law."

            Article XV of the Registrant's  Restated  Articles of Incorporation,
as  amended,  provides:  "To  the  fullest  extent  permitted  by  the  Colorado
Corporation  Code as the same exists or may hereafter be amended,  a director of
this corporation  shall not be liable to the corporation or its shareholders for
monetary  damages  for  breach of  fiduciary  duty as a  director.  Neither  the
amendment,  nor the repeal of this Article, nor the adoption of any provision of
the Articles of Incorporation inconsistent with this Article, shall eliminate or
reduce the protection  afforded by this Article to a director of the corporation
with respect to any matter which occurred, or any cause of action, suit or claim
which  but for  this  Article  would  have  accrued  or  arisen,  prior  to such
amendment, repeal or adoption."

Item 16.  Exhibits.

            Exhibits are listed in the Exhibit Index on page II-6 hereof.

Item 17.  Undertakings.

            The undersigned Registrant hereby undertakes:


            (1) To file,  during any  period in which  offers or sales are being
made, a post-effective  amendment to this Registration Statement: (i) to include
any  prospectus  required by Section  10(a)(3) of the Securities Act of 1933, as
amended (the "1993 Act");  (ii) to reflect in the Prospectus any facts or events
arising  after the  effective  date of the  Registration  Statement (or the most
recent  post-effective   amendment  thereof)  which,   individually  or  in  the
aggregate,  represent a fundamental  change in the  information set forth in the
Registration Statement;  provided,  however, that notwithstanding the foregoing,
any  increase  or  decrease  in the volume of  securities  offered (if the total
dollar value of securities  offered would not exceed that which was  registered)
and any  deviation  from the low or high end of the estimated  maximum  offering
range may be reflected in the form of prospectus  filed with the  Securities and
Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the changes in
volume  and price  represent  no more than a 20  percent  change in the  maximum
aggregate  offering price set forth in the  "Calculation  of  Registration  Fee"
table in the effective Registration Statement; and (iii) to include any material
information with respect to the plan of distribution not previously disclosed in
the  Registration  Statement or any material  change to such  information in the
Registration  Statement;  provided,  however,  that the Company  need not file a
post-effective  amendment to include the information  required to be included by
subsection  (i) or (ii) if such  information  is contained  in periodic  reports
filed  by  the  Registrant  pursuant  to  Section  13 or  Section  15(d)  of the
Securities  Exchange Act of 1934,  as amended  (the  "Exchange  Act"),  that are
incorporated by reference in the Registration Statement.

            (2) That,  for the purpose of  determining  any liability  under the
1933  Act,  each  such  post-effective  amendment  shall be  deemed  to be a new
registration  statement  relating to the

                                      II-2
<PAGE>

securities  offered  therein,  and the offering of such  securities at that time
shall be deemed to be the initial bona fide offering thereof.

            (3)  To  remove  from  registration  by  means  of a  post-effective
amendment  any of the  securities  being  registered  which remain unsold at the
termination of the offering.

            (4) That, for purposes of determining  any liability  under the 1933
Act, each filing of the Registrant's  annual report pursuant to Section 13(a) of
the  Exchange  Act  that is  incorporated  by  reference  in  this  Registration
Statement  shall be deemed to be a new  registration  statement  relating to the
securities offered herein and the offering of such securities at that time shall
be deemed to be the initial bona fide offering thereof.

            Insofar as  indemnification  for liabilities  arising under the 1933
Act may be  permitted to  directors,  officers  and  controlling  persons of the
Registrant  pursuant to the provisions  under Item 15 above,  or otherwise,  the
Registrant  has been advised that in the opinion of the  Securities and Exchange
Commission  such  indemnification  is against  public policy as expressed in the
1933  Act  and is,  therefore,  unenforceable.  In the  event  that a claim  for
indemnification  against  such  liabilities  (other  than  the  payment  by  the
Registrant of expenses  incurred or paid by a director,  officer or  controlling
person of the  Registrant  in the  successful  defense  of any  action,  suit or
proceeding)  is  asserted by such  director,  officer or  controlling  person in
connection with the securities being registered,  the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit  to a  court  of  appropriate  jurisdiction  the  question  whether  such
indemnification  by it is against public policy as expressed in the 1933 Act and
will be governed by final adjudication of such issue.

                                      II-3
<PAGE>


                               POWER OF ATTORNEY

            Each  director  and/or  officer of the  Registrant  whose  signature
appears below hereby appoints Wayne H. Brunetti and R.C. Kelly, and each of them
severally, as his or her attorneys-in-fact to sign in his or her name and on his
or her behalf,  in any and all  capacities  stated  below,  and to file with the
Securities   and  Exchange   Commission  any  and  all   amendments,   including
post-effective amendments, to this Registration Statement.

                                  SIGNATURES

            Pursuant to the  requirements  of the  Securities  Act of 1933,  the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-3 and has duly caused this Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized,  in the City and County of Denver and the State of Colorado,  on the
22nd day of October, 1996.

                              PUBLIC SERVICE COMPANY OF COLORADO

                              By:/s/R. C. Kelly
                              -------------------
                                 R.C. Kelly
                                 Senior Vice President, Finance, Treasurer and
                                 Chief Financial Officer

            Pursuant to the  requirements  of the Securities  Act of 1933,  this
Registration  Statement  has been signed below by the  following  persons in the
capacities and on the date indicated:
<TABLE>
<CAPTION>
<S>                                       <C>                                   <C>    

Signature                                 Title                                 Date

/s/Wayne H. Brunetti
- ---------------------------------

Wayne H. Brunetti, President and          Principal Executive Officer           October 22, 1996
Chief Executive Officer and Director


/s/R. C. Kelly
- ---------------------------------
R.C. Kelly, Senior Vice President,        Principal Financial Officer           October 22, 1996
Finance, Treasurer and Chief
Financial Officer

/s/ W. Wayne Brown
- ---------------------------------
W. Wayne Brown, Controller                Principal Accounting Officer          October 22, 1996

/s/D. D. Hock
- ---------------------------------
D.D. Hock, Chairman of the                Director                              October 22, 1996
Board and Director

                                      II-4
<PAGE>

/s/Collis P. Chandler, Jr.
- ---------------------------------
Collis P. Chandler, Jr.                   Director                              October 22, 1996

/s/Doris M. Drury
- ---------------------------------
Doris M. Drury                            Director                              October 22, 1996

/s/Thomas T. Farley
- ---------------------------------
Thomas T. Farley                          Director                              October 22, 1996

/s/Gayle L. Greer
- ---------------------------------
Gayle L. Greer                            Director                              October 22, 1996

/s/A. Barry Hirschfeld
- ---------------------------------
A. Barry Hirschfeld                       Director                              October 22, 1996

/s/George B. McKinley
- ---------------------------------
George B. McKinley                        Director                              October 22, 1996

/s/Will F. Nicholson, Jr.
- ---------------------------------
Will F. Nicholson, Jr.                    Director                              October 22, 1996

/s/J. Michael Powers
- ---------------------------------
J. Michael Powers                         Director                              October 22, 1996

/s/Thomas E. Rodriguez
- ---------------------------------
Thomas E. Rodriguez                       Director                              October 22, 1996

/s/Rodney E. Slifer
- ---------------------------------
Rodney E. Slifer                          Director                              October 22, 1996

/s/W. Thomas Stephens
- ---------------------------------
W. Thomas Stephens                        Director                              October 22, 1996

/s/Robert G. Tointon
- ---------------------------------
Robert G. Tointon                         Director                              October 22, 1996
</TABLE>
                                      II-5
<PAGE>




                                  EXHIBIT INDEX

1           Form of  Distribution Agreement

3(a)*       Restated  Articles of  Incorporation of the Registrant dated July 9,
            1990 (Form S-3, File No. 33-54877 - Exhibit 3(a)).

3(b)*       Articles of Amendment of the Restated  Articles of  Incorporation of
            the  Registrant dated  May 11, 1994  (Form  S-3, File No. 33-54877 -
            Exhibit 3(b)).

4(a)(1)*    Indenture,  dated as of December 1, 1939, providing for the issuance
            of First Mortgage Bonds (Form 10 for 1946-Exhibit (B-1)).

4(a)(2)*    Indentures supplemental to Indenture dated as of December 1, 1939:



<TABLE>
<CAPTION>

                   Previous Filing:                                       Previous Filing:
                     Form; Date or                                         Form, Date or         Exhibit
Dated as of           File No.           Exhibit No.     Dated as of          File No.              No.
- -----------           --------           -----------     -----------          --------              ---
<S>                <C>                    <C>           <C>               <C>                     <C>    
Mar. 14, 1941        10, 1946               B-2         July 1, 1968      8-K, July 1968             2
May 14, 1941         10, 1946               B-3         Apr. 25, 1969     8-K, Apr. 1969             1
Apr. 28, 1942        10, 1946               B-4         Apr. 21, 1970     8-K, Apr. 1970             1
Apr. 14, 1943        10, 1946               B-5         Sept. 1, 1970     8-K, Sept. 1970            2
Apr. 27, 1944        10, 1946               B-6         Feb. 1, 1971      8-K, Feb. 1971             2
Apr. 18, 1945        10, 1946               B-7         Aug. 1, 1972      8-K, Aug. 1972             2
Apr. 23, 1946       10-K, 1946              B-8         June 1, 1973      8-K, June 1973             1
Apr. 9, 1947        10-K, 1946              B-9         Mar. 1, 1974      8-K, Apr. 1974             2
June 1, 1947       S-1, (2-7075)            7(b)        Dec. 1, 1974      8-K, Dec. 1974             1
Apr. 1, 1948       S-1, (2-7671)          7(b)(1)       Oct. 1, 1975      S-7, (2-60082)          2(b)(3)
May 20, 1948       S-1, (2-7671)          7(b)(2)       Apr. 28, 1976     S-7, (2-60082)          2(b)(4)
Oct. 1, 1948        10-K, 1948               4          Apr. 28, 1977     S-7, (2-60082)          2(b)(5)
Apr. 20, 1949       10-K, 1949               1          Nov. 1, 1977      S-7, (2-62415)          2(b)(3)
Apr. 24, 1950      8-K, Apr.1950             1          Apr. 28, 1978     S-7, (2-62415)          2(b)(4)
Apr. 18, 1951      8-K, Apr. 1951            1          Oct. 1, 1978       10-K, 1978               D(1)
Oct. 1, 1951       8-K, Nov. 1951            1          Oct. 1, 1979      S-7, (2-66484)          2(b)(3)
Apr. 21, 1952      8-K, Apr. 1952            1          Mar. 1, 1980       10-K, 1980              4(c)
Dec. 1, 1952       S-9, (2-11120)         2(b)(9)       Apr. 28, 1981     S-16,(2-74923)           4(c)
Apr. 15, 1953      8-K, Apr. 1953            2          Nov. 1, 1981      S-16,(2-74923)           4(d)
April 19, 1954     8-K, Apr. 1954            1          Dec. 1, 1981       10-K, 1981              4(c)
Oct. 1, 1954       8-K, Oct. 1954            1          Apr. 29, 1982      10-K, 1982              4(c)
Apr. 18, 1955      8-K, Apr. 1955            1          May 1, 1983        10-K, 1983              4(c)
Apr. 24, 1956       10-K, 1956               1          Apr. 30, 1984     S-3,(2-95814)            4(c)
May 1, 1957        S-9, (2-13260)         2(b)(15)      Mar. 1, 1985       10-K, 1985              4(c)
April 10, 1958     8-K, Apr. 1958            1          Nov. 1, 1986       10-K, 1986              4(c)
May 1, 1959        8-K, May 1959             2          May 1, 1987        10-K, 1987              4(c)
Apr. 18, 1960      8-K, Apr. 1960            1          July 1, 1990      S-3,(33-37431)           4(c)
Apr. 19, 1961      8-K, Apr. 1961            1          Dec. 1, 1990       10-K, 1990              4(c)
Oct. 1, 1961       8-K, Oct. 1961            2          Mar. 1, 1992       10-K, 1992              4(d)
Mar. 1, 1962       8-K, Mar. 1962           3(a)        Apr. 1, 1993    10-Q, June 30, 1993        4(a)
June 1, 1964       8-K, June 1964            1          June 1, 1993    10-Q, June 30, 1993        4(b)
May 1, 1966        8-K, May 1966             2          Nov. 1, 1993      S-3, (33-51167)        4(a)(3)
July 1, 1967       8-K, July 1967            2          Jan. 1, 1994    10-K, Dec. 31, 1993      4(a)(3)
                                                        Sept. 2, 1994     8-K, Sept. 1994          4(a)
                                                        May 1, 1996     10-Q, June 30, 1996        4(a)

</TABLE>

4(a)(3)     Form of Supplemental Indenture establishing series of First Mortgage
            Bonds under the Indenture, dated as of December 1, 1939.

                                      II-6
<PAGE>

4(b)(1)*    Indenture,  dated as of October 1, 1993,  providing for the issuance
            of First  Collateral  Trust Bonds (Form 10-Q,  September  30, 1993 -
            Exhibit 4(a)).

4(b)(2)*    Indentures supplemental to Indenture dated as of October 1, 1993:
<TABLE>
<CAPTION>

                        Previous Filing:
                         Form; Date or      Exhibit
  Dated as of               File No.           No.
  -----------               --------           ---
<S>                  <C>                     <C> 

November 1, 1993        S-3, (33-51167)      4(b)(2)
January 1, 1994      10-K, Dec. 31, 1993     4(b)(3)
September 2, 1994      8-K, Sept. 1994         4(b)
May 1, 1996          10-Q, June 30, 1996       4(b)
                        
</TABLE>

4(b)(3) Form of Supplemental  Indenture  establishing series of First Collateral
        Trust Bonds under the Indenture, dated as of October 1, 1993.

5       Opinion   of  LeBoeuf,  Lamb,  Greene &  MacRae,  L.L.P., a  partnership
        including professional corporations.

12      Computation  of  Ratio  of  Consolidated  Earnings to Consolidated Fixed
        Charges.

15      Letter of Arthur Andersen LLP  regarding  interim  unaudited   financial
        information.

23(a)   Consent of Arthur Andersen LLP.

23(b)   Consent  of  LeBoeuf,  Lamb,  Greene &   MacRae,  L.L.P.,  a partnership
        including  professional corporations is included in its opinion filed as
        Exhibit 5.

24      Power of Attorney is included on page II-4 hereof.

25      Statement   of   Eligibility   of   First   Trust  of New York, National
        Association, as  successor   trustee  under  the  Indenture, dated as of
        October 1, 1993.

- -----------------
* Previously filed as indicated and incorporated herein by reference.



                                      II-7


                                                                       Exhibit 1



                      PUBLIC SERVICE COMPANY OF COLORADO
                           (a Colorado corporation)

                      Secured Medium-Term Notes, Series B
            Due From Nine Months to Thirty Years from Date of Issue


                            DISTRIBUTION AGREEMENT





                                          [DATE]


MERRILL LYNCH & CO.
Merrill Lynch, Pierce, Fenner & Smith
            Incorporated
World Financial Center
10th Floor, North Tower
New York, New York  10281-1310

GOLDMAN, SACHS & CO.
85 Broad Street
New York, New York  10004


Dear Sirs:

      Public  Service  Company  of  Colorado,   a  Colorado   corporation   (the
"Company"),  confirms its  agreement  with Merrill Lynch & Co.,  Merrill  Lynch,
Pierce,  Fenner & Smith Incorporated and Goldman,  Sachs & Co. (each an "Agent";
collectively, the "Agents") with respect to the issue and sale by the Company of
its  Secured  Medium-Term  Notes,  Series B (being a series of First  Collateral
Trust  Bonds)  (the  "Notes").  The Notes are to be issued  under the  Company's
Indenture  dated as of October 1, 1993,  as heretofore  supplemented  by various
supplemental indentures, including a supplemental indenture dated as of November
1, 1996, to First Trust of New York, National Association, as successor trustee


<PAGE>



(the "Trustee") to Morgan Guaranty Trust Company of New York (formerly  Guaranty
Trust  Company  of  New  York).  Said  Indenture  as so  supplemented  and to be
supplemented  is  hereinafter  called  the  "Indenture"  and  such  supplemental
indenture dated as of November 1, 1996 is hereinafter  called the  "Supplemental
Indenture".  As of the date hereof,  the Company has authorized the issuance and
sale of up to $250,000,000 aggregate principal amount of Notes to or through the
Agents pursuant to the terms of this Agreement.

      This  Agreement  provides both for the sale of Notes by the Company to one
or more Agents as principal for resale to investors and other purchasers and for
the sale of Notes by the Company directly to investors (as may from time to time
be specified  by the Company and agreed to by the  applicable  Agent),  in which
case such Agent will act as an agent of the Company in  soliciting  purchases of
the Notes.  The Company  may also sell Notes  directly  to  investors  and other
investors on its own behalf and not through an Agent acting as agent.

      The Company has filed with the  Securities  and Exchange  Commission  (the
"SEC") a registration  statement on Form S-3 (No. 333-[ ]) for the  registration
of First Collateral Trust Bonds,  including the Notes,  under the Securities Act
of  1933  (the  "1933  Act")  and  the  offering  thereof  from  time to time in
accordance  with Rule 415 of the rules and regulations of the SEC under the 1933
Act (the "1933 Act Regulations"). Such registration statement, [as amended], was
declared  effective by the SEC at [ ], Eastern  Standard Time, on [ ] (the later
of such  time and date or the time  and  date of the  filing  thereafter  of the
Company's  most  recent  Annual  Report  on  Form  10-K  (a  "10-K  Report")  is
hereinafter  called the "Effective Date"). The Indenture has been duly qualified
under the Trust  Indenture  Act of 1939,  as  amended  (the  "1939  Act").  Such
registration  statement and the prospectus  constituting a part thereof, and any
prospectus  supplement and pricing supplement  relating to the Notes,  including
all documents incorporated therein by reference, as from time to time amended or
supplemented by the filing of documents pursuant to the Securities  Exchange Act
of 1934, as amended (the "1934 Act"), or the 1933 Act or otherwise, are referred
to herein as the "Registration  Statement" and the  "Prospectus",  respectively,
except  that if any  revised  prospectus  shall be provided to the Agents by the
Company for use in  connection  with the  offering of the Notes,  whether or not
such revised  prospectus is required to be filed by the Company pursuant to Rule
424(b) of the 1933 Act Regulations,  the term  "Prospectus"  shall refer to such
revised  prospectus  from and after the time it is first  provided to the Agents
for such use.




                                    -2-


<PAGE>



SECTION 1.  Appointment as Agents.

      (a)  Appointment  of Agents.  Subject to the terms and  conditions  stated
herein,  the  Company  hereby  agrees  that Notes will be sold to or through the
Agents,  except that the Company reserves the right to sell the Notes on its own
behalf directly to investors in those jurisdictions where it is authorized to do
so and,  from time to time,  to  appoint  additional  agents to sell the  Notes,
provided  that the Company  shall  furnish the Agents  with  reasonable  advance
notification  of the  appointment of any additional  agent to sell the Notes and
provided  further  that such  additional  agents  shall be  required  to execute
distribution  agreements  in form and  substance  substantially  similar to this
Agreement.

      (b) Sale of Notes.  The Company shall not sell or approve the solicitation
of purchases of Notes in excess of the amount which shall be  authorized  by the
Company  from  time to time or in excess of the  aggregate  principal  amount of
Notes registered pursuant to the Registration  Statement.  The Agents shall have
no  responsibility  for  maintaining  records  with  respect  to  the  aggregate
principal  amount of Notes sold, or of otherwise  monitoring the availability of
Notes for sale, under the Registration Statement.

      (c)  Purchases as Principal.  The Agents shall not have any  obligation to
purchase  Notes from the Company as principal,  but one or more Agents may agree
from time to time to purchase  Notes as principal  for resale to  investors  and
other purchasers  determined by such Agent or Agents. Any such purchase of Notes
by an Agent as principal shall be made in accordance with Section 3(a) hereof.

      (d)  Solicitations  as Agent. If requested by the Company and agreed to by
an  Agent,  such  Agent,  acting  solely  as agent  for the  Company  and not as
principal,  will solicit  purchases of the Notes. Such Agent will communicate to
the Company,  orally,  each offer to purchase Notes solicited by it on an agency
basis, other than those offers rejected by such Agent. Such Agent shall have the
right, in its discretion reasonably  exercised,  to reject any proposed purchase
of Notes,  as a whole or in part, and any such  rejection  shall not be deemed a
breach of its agreement  contained herein.  The Company may accept or reject any
proposed  purchase  of  Notes,  in whole  or in  part.  Such  Agent  shall  make
reasonable  efforts  to assist  the  Company in  obtaining  performance  by each
purchaser whose offer to purchase Notes has been solicited by it and accepted by
the Company. Such Agent shall not have any liability to the Company in the event
that any such purchase is not consummated  for any reason.  If the Company shall
default on its  obligation  to deliver  Notes to a purchaser  whose offer it has
accepted, the Company shall (i) hold such Agent harmless against any loss, claim
or damage  arising  from or as a result of such  default by the Company and (ii)
pay to such Agent any commission to which it would  otherwise be entitled absent
such default.

                                    -3-


<PAGE>




      (e) Reliance. The Company and the Agents agree that any Notes purchased by
one or more Agents as principal shall be purchased,  and any Notes the placement
of which an Agent arranges as agent shall be placed by such Agent in reliance on
the  representations,  warranties,  covenants  and  agreements  of  the  Company
contained  herein and on the terms and  conditions  and in the  manner  provided
herein.




SECTION 2.  Representations and Warranties.

      (a) The  Company  represents  and  warrants  to each  Agent as of the date
hereof,  as of the date of each  acceptance  by the  Company of an offer for the
purchase of Notes  (whether to such Agent as  principal or through such Agent as
agent),  as of the date of each  delivery  of Notes  (whether  to such  Agent as
principal or through such Agent as agent) (the date of each such  delivery to an
Agent as principal being hereafter  referred to as a "Settlement  Date"), and as
of the times  referred to in Section 7(a) hereof  (each of the times  referenced
above being referred to hereafter as a "Representation Date"), as follows:

              (i) Registration Statement and Prospectus.  At the Effective Date,
      the  Registration  Statement  and the  Indenture  complied,  and as of the
      applicable  Representation Date will comply, in all material respects with
      the requirements of the 1933 Act and the 1933 Act Regulations and the 1939
      Act and the rules and regulations of the SEC promulgated  thereunder.  The
      Registration  Statement,  at the Effective Date, did not, and at each time
      thereafter at which any amendment to the  Registration  Statement  becomes
      effective and as of the applicable  Representation Date, will not, contain
      an untrue  statement of a material  fact or omit to state a material  fact
      required to be stated therein or necessary to make the statements  therein
      not misleading.  The Prospectus, as of the date hereof does not, and as of
      the applicable  Representation  Date will not, include an untrue statement
      of a material fact or omit to state a material fact  necessary in order to
      make the statements therein, in the light of the circumstances under which
      they   were   made,   not   misleading;   provided,   however,   that  the
      representations  and  warranties  in this  subsection  shall  not apply to
      statements in or omissions from the  Registration  Statement or Prospectus
      made in reliance upon and in conformity with information  furnished to the
      Company in writing by the  Agents  expressly  for use in the  Registration
      Statement  or  Prospectus  or to that part of the  Registration  Statement
      which  constitutes the Trustee's  Statement of Eligibility  under the 1939
      Act (Form T-1).



                                    -4-


<PAGE>



             (ii)  Incorporated   Documents.   The  documents   incorporated  by
      reference  into the  Prospectus,  at the time they were or  hereafter  are
      filed with the SEC, complied or when so filed will comply, as the case may
      be, in all material respects with the requirements of the 1934 Act and the
      rules and regulations of the SEC thereunder (the "1934 Act  Regulations"),
      and, when read together and with the other  information in the Prospectus,
      did not and will not  contain an untrue  statement  of a material  fact or
      omit to state a material fact  required to be stated  therein or necessary
      in order to make the statements therein, in the light of the circumstances
      under which they were or are made, not misleading.

            (iii)  Accountants.  The  accountants  who  certified  the financial
      statements and supporting  schedules included or incorporated by reference
      in the  Registration  Statement and the Prospectus are independent  public
      accountants as required by the 1933 Act and the 1933 Act Regulations.

             (iv)  Financial  Statements.   The  financial  statements  and  any
      supporting  schedules  of the  Company and its  consolidated  subsidiaries
      included or  incorporated by reference in the  Registration  Statement and
      the Prospectus  present fairly the consolidated  financial position of the
      Company and its  consolidated  subsidiaries  as at the dates indicated and
      the  results of their  operations  for the  periods  specified;  except as
      otherwise stated therein,  said financial statements have been prepared in
      conformity  with generally  accepted  accounting  principles  applied on a
      consistent basis; and the supporting schedules included or incorporated by
      reference in the Registration  Statement and the Prospectus present fairly
      the information required to be stated therein.

              (v)  Material   Changes  or  Material   Transactions.   Since  the
      respective  dates as of  which  information  is given in the  Registration
      Statement  and the  Prospectus,  except as  otherwise  stated  therein  or
      contemplated thereby, (A) there has been no material adverse change in the
      business,  property or condition,  financial or otherwise,  of the Company
      and its subsidiaries considered as one enterprise,  whether or not arising
      in  the  ordinary  course  of  business,   and  (B)  there  have  been  no
      transactions entered into by the Company or any of its subsidiaries, other
      than those in the  ordinary  course of  business,  which are  material  in
      relation to the Company and its subsidiaries considered as one enterprise;
      and, except as so stated or  contemplated,  neither the Company nor any of
      its subsidiaries has any contingent  obligations which are material to the
      Company and its subsidiaries considered as one enterprise.



                                    -5-


<PAGE>



            (vi) Due Incorporation and Qualification.  The Company has been duly
      incorporated  and is validly  existing as a  corporation  in good standing
      under the laws of the State of Colorado with corporate power and authority
      to own,  lease and operate its  properties  and to conduct its business as
      described in the Prospectus and the Company is duly qualified as a foreign
      corporation  to  transact  business  and  is  in  good  standing  in  each
      jurisdiction in which such qualification is required, whether by reason of
      the  ownership or leasing of property or the conduct of  business,  except
      where the  failure to so qualify or be in good  standing  would not have a
      material adverse effect on the business, property or condition,  financial
      or  otherwise,  of the  Company  and its  subsidiaries  considered  as one
      enterprise.

            (vii)  Authorization  and Validity of this Agreement,  the Indenture
      and the Notes. This Agreement has been duly and validly  authorized by the
      Company and, upon  execution and delivery by the Agents and subject to any
      principles   of  public   policy   limiting   the  right  to  enforce  the
      indemnification  provisions  contained herein, will be a valid and binding
      agreement of the Company;  the  Indenture and the  Supplemental  Indenture
      have  each been duly and  validly  authorized  by the  Company  and,  upon
      execution and delivery of the Supplemental  Indenture by the Trustee,  the
      Indenture  (including  the  Supplemental  Indenture)  will be a valid  and
      binding mortgage of the Company  enforceable in accordance with its terms,
      except as  enforcement  thereof may be limited by laws and  principles  of
      equity  affecting  generally  the  enforcement  of  mortgagees'  and other
      creditors' rights, including without limitation, bankruptcy and insolvency
      laws and state  laws  which  affect the  enforcement  of certain  remedial
      provisions of the  Indenture;  the issuance and sale by the Company of the
      Notes  pursuant  to  this  Agreement  have  been  duly  authorized  by all
      necessary  corporate action and, when issued,  authenticated and delivered
      by the  Company  pursuant  to this  Agreement  and the  Indenture  against
      payment of the consideration therefor, the Notes will be valid and binding
      obligations of the Company,  enforceable  in accordance  with their terms,
      except as  enforcement  thereof may be limited by laws and  principles  of
      equity  affecting  generally  the  enforcement  of  mortgagees'  and other
      creditors' rights, including without limitation, bankruptcy and insolvency
      laws and state  laws  which  affect the  enforcement  of certain  remedial
      provisions  of the  Indenture;  and the  Notes and the  Indenture  will be
      substantially  in the form heretofore  delivered to the Agents and conform
      in all material  respects to all statements  relating thereto contained in
      the  Prospectus;  and the  Notes  will be  entitled  to the  benefits  and
      security of the Indenture, and will be secured equally and ratably (except
      to the extent that any sinking,  amortization,  improvement  or other fund
      may afford

                                    -6-


<PAGE>



      additional security for the bonds of any particular series) with all other
      bonds outstanding under the Indenture.

            (viii)  Class A Bonds.  The  issuance and delivery by the Company of
      the Class A Bonds (as  defined in the  Indenture)  to be made the basis of
      the  authentication  and  delivery of the Notes (the "Class A Bonds") have
      been duly authorized by all necessary  corporate action;  and when (i) the
      Class A Bonds have been issued, authenticated and delivered to the Trustee
      pursuant  to  the   Indenture   and  (ii)  the  Notes  have  been  issued,
      authenticated  and delivered to the Purchasers  pursuant to this Agreement
      against payment of the consideration  therefor specified herein, the Class
      A Bonds will be valid and binding obligations of the Company,  enforceable
      in  accordance  with their  terms,  except as  enforcement  thereof may be
      limited  by  laws  and  principles  of  equity  affecting   generally  the
      enforcement of mortgagees' and other creditors' rights,  including without
      limitation  bankruptcy and insolvency laws and state laws which affect the
      enforcement of certain  remedial  provisions of the PSCO 1939 Mortgage (as
      defined in the  Indenture),  and will be entitled  to the  benefits of the
      PSCO 1939 Mortgage.

            (ix) No Defaults.  The Company is not in violation of its charter or
      by-laws or in default in the  performance  or  observance  of any material
      obligation,  agreement,  covenant or condition  contained in any contract,
      indenture,  mortgage,  loan agreement,  note, lease or other instrument to
      which it is a party or by which it or any of them or their  properties may
      be bound or any law, administrative  regulation or administrative or court
      order or  decree  except  to the  extent  set  forth  in the  Registration
      Statement and the  Prospectus or except to the extent that such  violation
      or  default  would not have a  material  adverse  effect on the  business,
      property or  condition,  financial  or  otherwise,  of the Company and its
      subsidiaries considered as one enterprise;  and the execution and delivery
      of this Agreement and the  Supplemental  Indenture,  the incurrence of the
      obligations  herein  set forth and the  consummation  of the  transactions
      contemplated  herein and therein  will not conflict  with or  constitute a
      breach of, or default  under or (other  than under the  Indenture  and the
      PSCO 1939 Mortgage with respect to the Notes and the Class A Bonds) result
      in the creation or imposition of any lien,  charge or encumbrance upon any
      property or assets of the Company pursuant to any contract,  lease,  note,
      mortgage,  indenture,  loan  agreement  or other  instrument  to which the
      Company  is a party or by  which  it may be  bound or to which  any of the
      property or assets of the Company is subject,  nor will such action result
      in any  violation  of the  provisions  of the  charter  or  by-laws of the
      Company or any law,  administrative  regulation or administrative or court
      order or decree.


                                    -7-


<PAGE>



            (x) Legal Proceedings;  Contracts. Except as may be set forth in the
      Registration  Statement and the  Prospectus,  there is no action,  suit or
      proceeding before or by any court or governmental agency or body, domestic
      or foreign, now pending,  or, to the knowledge of the Company,  threatened
      against or affecting, the Company or any of its subsidiaries,  which would
      result  in any  material  adverse  change  in the  business,  property  or
      condition,  financial or  otherwise,  of the Company and its  subsidiaries
      considered  as one  enterprise,  or which would  materially  and adversely
      affect the  consummation of this Agreement;  and there are no contracts or
      documents of the Company or any of its subsidiaries  which are required to
      be filed as exhibits to the  Registration  Statement by the 1933 Act or by
      the 1933 Act Regulations which have not been so filed.

            (xi) Authorization, Approval and Consent. The Company has filed with
      The Public  Utilities  Commission of the State of Colorado (the  "Colorado
      Commission")  an  application  with  respect to, among other  things,  the
      issuance and sale of the Company's debt  securities,  including the Notes,
      and the Colorado Commission has issued its order authorizing and approving
      such issuance and sale.  If the  above-mentioned  order  continues in full
      force and effect, no further consent,  order or authorization of or decree
      or approval by the Colorado  Commission or any other court or governmental
      or  regulatory  authority  or body is  necessary  in  connection  with the
      consummation  by the  Company  of the  transactions  contemplated  by this
      Agreement or the issuance and sale by the Company of the Notes pursuant to
      this  Agreement,  except that there must be compliance with the securities
      laws in the jurisdictions in which the Notes are to be offered and sold.

            (xii) Ratings.  The medium-term  note program  pursuant to which the
      Notes are being issued (the  "Program") as well as the Notes are rated [ ]
      by Standard & Poor's Ratings Service and [ ] by Moody's Investors Service,
      Inc.,  or such  other  rating  as to which  the  Company  shall  have most
      recently notified the Agents pursuant to Section 4(a) hereof.

            (xiii)  Subsidiaries.  Each  subsidiary  of the  Company  which is a
      significant subsidiary (each, a "Significant  Subsidiary"),  as defined in
      Rule  405 of  Regulation  C of the  1933 Act  Regulations,  has been  duly
      incorporated  and is validly  existing as a  corporation  in good standing
      under the laws of the  jurisdiction  of its  incorporation,  has corporate
      power and  authority  to own,  lease and  operate  its  properties  and to
      conduct its business as described in the Prospectus, and is duly qualified
      as a foreign  corporation to transact  business and is in good standing in
      each  jurisdiction  in which such  qualification  is required,  whether by
      reason of the ownership or leasing of property or the conduct of

                                    -8-


<PAGE>



      business,  except  where the failure to so qualify or be in good  standing
      would not have a material  adverse  effect on the  business,  property  or
      condition,  financial or  otherwise,  of the Company and its  subsidiaries
      considered as one enterprise;  all of the issued and  outstanding  capital
      stock of each Significant  Subsidiary has been duly and validly issued and
      is fully paid and  non-assessable;  and all of the  capital  stock of each
      Significant   Subsidiary  owned  by  the  Company,   directly  or  through
      subsidiaries,  is owned free and clear of any security interest, mortgage,
      pledge,  lien,  encumbrance,  claim or  equity  except  that the  stock of
      certain of such subsidiaries is pledged under the PSCO 1939 Mortgage.

      (b) Additional  Certifications.  Any certificate  signed by any officer of
the Company and  delivered to one or more Agents or to counsel for the Agents in
connection  with an  offering  of Notes to one or more  Agents as  principal  or
through an Agent as agent shall be deemed a  representation  and warranty by the
Company to such Agent or Agents as to the matters covered thereby on the date of
such certificate.


SECTION 3.  Purchases as Principals; Solicitations as Agents.

      (a) Purchases as Principals. Unless otherwise specified by the Company and
agreed  to by an  Agent,  Notes  shall be  purchased  by one or more  Agents  as
principal in  accordance  with terms agreed upon by such Agent or Agents and the
Company (which terms, unless otherwise agreed,  shall, to the extent applicable,
include  those terms  specified  in Exhibit A hereto and be agreed upon  orally,
with written confirmation prepared by such Agent or Agents and facsimiled to the
Company).  An Agent's  commitment to purchase Notes as principal shall be deemed
to have been  made on the basis of the  representations  and  warranties  of the
Company herein contained and shall be subject to the terms and conditions herein
set forth.  Unless the context  otherwise  requires,  references herein to "this
Agreement"  shall include the agreement of one or more Agents to purchase  Notes
from the Company as principal.  Each purchase of Notes, unless otherwise agreed,
shall be at a discount from the principal amount of each such Note equivalent to
the applicable  commission set forth in Schedule A hereto. The Agents may engage
the services of any other broker or dealer in connection  with the resale of the
Notes  purchased  by them as  principal  and may allow all or any portion of the
discount  received in connection  with such  purchases  from the Company to such
brokers and dealers. At the time of each purchase of Notes by one or more Agents
as  principal,  such Agent or Agents  shall  specify  the  requirements  for the
stand-off  agreement,  officers'  certificate,  opinions  of counsel and comfort
letter pursuant to Sections 4(l), 7(a), 7(b) and 7(c) hereof.

     (b)  Solicitations  as  Agents.  On the  basis of the  representations  and
warranties herein contained, but subject to

                                    -9-


<PAGE>



the terms and  conditions  herein set forth,  when  agreed by the Company and an
Agent, such Agent, as an agent of the Company,  will use its reasonable  efforts
to solicit  offers to purchase the Notes upon the terms and conditions set forth
herein  and  in the  Prospectus.  The  Agents  are  not  authorized  to  appoint
sub-agents  with  respect to Notes sold  through  them as agent.  All Notes sold
through an Agent as agent will be sold at 100% of their principal  amount unless
otherwise agreed to by the Company and such Agent.

      The  Company  reserves  the  right,  in its sole  discretion,  to  suspend
solicitation  of offers to purchase  the Notes  through  the Agents,  as agents,
commencing  at any  time  for any  period  of time  or  permanently.  As soon as
practicable  after  receipt of  instructions  from the Company,  the Agents will
suspend solicitation of offers to purchase the Notes from the Company until such
time as the  Company  has  advised  the  Agents  that such  solicitation  may be
resumed.

      The  Company  agrees  to pay  each  Agent a  commission,  in the form of a
discount,  equal to the  applicable  percentage of the principal  amount of each
Note sold by the Company as a result of a solicitation made by such Agent as set
forth in Schedule A hereto.

      (c)  Administrative  Procedures.  The  purchase  price,  interest  rate or
formula, maturity date and other terms of the Notes (as applicable) specified in
Exhibit A hereto shall be agreed upon by the Company and the applicable Agent or
Agents and specified in a pricing supplement to the Prospectus (each, a "Pricing
Supplement") to be prepared in connection with each sale of Notes. Except as may
be otherwise specified in the applicable Pricing  Supplement,  the Notes will be
issued  in  denominations  of U.S.  $100,000  or any  larger  amount  that is an
integral multiple of U.S. $1,000.  Administrative procedures with respect to the
sale of Notes shall be agreed upon from time to time by the Agents,  the Company
and the Trustee (the "Procedures"). The Agents and the Company agree to perform,
and the  Company  agrees  to  cause  the  Trustee  to agree  to  perform,  their
respective duties and obligations  specifically provided to be performed by them
in the Procedures.


SECTION 4.  Covenants of the Company.

      The Company covenants with each Agent as follows:

      (a)  Notice  of  Certain  Events.  The  Company  will  notify  the  Agents
immediately,  and confirm the notice in writing, (i) of the effectiveness of any
amendment to the Registration Statement,  (ii) of the transmittal to the SEC for
filing of any amendment or  supplement  to the  Prospectus or any document to be
filed  pursuant to the 1934 Act which will be  incorporated  by reference in the
Prospectus,  (iii) of the receipt of any  comments  from the SEC with respect to
the Registration Statement or the Prospectus,

                                    -10-


<PAGE>



(iv) of any request by the SEC for any amendment to the  Registration  Statement
or any amendment or supplement to the Prospectus or for additional  information,
and  (v)  of  the  issuance  by  the  SEC  of  any  stop  order  suspending  the
effectiveness of the Registration Statement or the initiation of any proceedings
for that purpose.  The Company will make every reasonable  effort to prevent the
issuance  of any stop  order and,  if any stop  order is  issued,  to obtain the
lifting thereof at the earliest possible moment.  In addition,  the Company will
notify  the  Agents  if  the  rating  assigned  by  any  nationally   recognized
statistical  rating  organization  to the Program or any debt  securities of the
Company shall have been changed,  or if any such rating  organization shall have
publicly  announced  that it has under  surveillance  or review,  with  possible
negative  implications,  its rating of the Program or any debt securities of the
Company or shall have withdrawn the rating of the Program or any debt securities
of the Company, promptly after learning of any such event.

      (b) Notice of Certain Proposed  Filings.  Except as otherwise  provided in
subsection  (j) of this  Section 4, the  Company  will give the  Agents  advance
notice of its intention to file or prepare any additional registration statement
with respect to the  registration  of  additional  Notes,  any  amendment to the
Registration  Statement or any amendment or supplement to the Prospectus  (other
than a Pricing  Supplement),  whether by the filing of documents pursuant to the
1934 Act, the 1933 Act or  otherwise,  and will furnish to the Agents  copies of
any such amendment or supplement or other documents a reasonable time in advance
of such filing or use.

      (c) Copies of the Registration  Statement and the Prospectus.  The Company
will  deliver to each Agent one (1) signed and as many  conformed  copies of the
Registration  Statement  (as  originally  filed) and of each  amendment  thereto
(including  exhibits filed therewith or  incorporated  by reference  therein and
documents  incorporated  by  reference  in the  Prospectus)  as the  Agents  may
reasonably request. The Company will furnish to the Agents as many copies of the
Prospectus (as amended or supplemented)  as the Agents shall reasonably  request
so long as the Agents are required to deliver a Prospectus  in  connection  with
sales or solicitations of offers to purchase the Notes.

      (d)  Revisions  of  Prospectus  -- Material  Changes.  Except as otherwise
provided  in  subsection  (j) of this  Section  4, if any event  shall  occur or
condition exist as a result of which it is necessary,  in the opinion of counsel
for the Agents or counsel for the Company,  to further amend or  supplement  the
Prospectus in order that the Prospectus will not include an untrue  statement of
a material  fact or omit to state any material  fact  necessary in order to make
the statements therein not misleading in the light of the circumstances existing
at the time it is delivered to a purchaser,  or if it shall be necessary, in the
opinion  of  either  such  counsel,  to amend  or  supplement  the  Registration
Statement or the Prospectus in order to comply with the requirements of the

                                    -11-


<PAGE>



1933 Act or the 1933 Act Regulations,  the Company shall give immediate  notice,
confirmed  in  writing,  to the  Agents to cease the  solicitation  of offers to
purchase  the Notes in their  capacity as agents and to cease sales of any Notes
the Agents may then own as principals, and the Company will promptly prepare and
file with the SEC such  amendment  or  supplement,  whether by filing  documents
pursuant to the 1934 Act,  the 1933 Act or  otherwise,  as may be  necessary  to
correct such untrue statement or omission or to make the Registration  Statement
and Prospectus comply with such requirements.

      (e)  Periodic  Financial  Information.  Except as  otherwise  provided  in
subsection  (j) of this  Section 4, on the date on which there shall be released
to the general public interim  financial  statement  information  related to the
Company with  respect to each of the first three  quarters of any fiscal year or
preliminary financial statement information with respect to any fiscal year, the
Company shall furnish such information to the Agents, confirmed in writing.

      (f)  Prospectus  Revisions  -- Audited  Financial  Information.  Except as
otherwise provided in subsection (j) of this Section, on the date on which there
shall be released to the general  public  financial  information  included in or
derived from the audited  financial  statements of the Company for the preceding
fiscal year, the Company shall furnish such information to the Agents, confirmed
in writing.

      (g) Earnings Statements.  The Company will make generally available to its
security  holders as soon as  practicable,  but not later than 90 days after the
close of the period covered  thereby,  an earnings  statement (in form complying
with the  provisions  of Rule 158 under the 1933 Act) covering each twelve month
period  beginning,  in each case,  not later than the first day of the Company's
fiscal quarter next following the "effective date" (as defined in such Rule 158)
of the Registration Statement with respect to each sale of Notes.

      (h) Blue Sky  Qualifications.  The Company will  endeavor,  in cooperation
with the Agents, to qualify the Notes for offering and sale under the applicable
securities laws of such states and other  jurisdictions  of the United States as
the Agents may designate, and will maintain such qualifications in effect for as
long as may be required for the  distribution of the Notes;  provided,  however,
that the Company  shall not be obligated to file any general  consent to service
of process or to qualify as a foreign  corporation in any  jurisdiction in which
it is not so qualified. The Company will file such statements and reports as may
be  required  by the laws of each  jurisdiction  in which  the  Notes  have been
qualified as provided above.  The Company will promptly advise the Agents of the
receipt by the Company of any notification with respect to the suspension of the
qualification  of the Notes for sale in any such  state or  jurisdiction  or the
initiation or threatening of any proceeding for such purpose.

                                    -12-


<PAGE>




      (i) 1934 Act Filings.  The Company,  during the period when the Prospectus
is required  to be  delivered  under the 1933 Act or the 1934 Act in  connection
with sales of the Notes,  will file all documents  required to be filed with the
SEC pursuant to Sections  13(a),  13(c),  14 or 15(d) of the 1934 Act within the
time periods prescribed by the 1934 Act and the 1934 Act Regulations.

      (j) Suspension of Certain  Obligations.  The Company shall not be required
to comply  with the  provisions  of  subsections  (b),  (d),  (e) or (f) of this
Section 4 or of subsections  (a), (b), (c) or (d) of Section 7 during any period
from the time the Agents shall have suspended  solicitation  of purchases of the
Notes in their  capacity  as agents  pursuant  to a request  from the Company to
cease such  solicitations,  until such time as the Company  notifies  the Agents
that  solicitation  of  purchases  of the  Notes  should be  resumed;  provided,
however, that compliance with such subsections shall be required for any portion
of such period during which any Agent has notified the Company that it holds any
Notes purchased hereunder as principal pursuant hereto.

      (k) Preparations of Pricing  Supplements.  The Company will prepare,  with
respect to any Notes to be sold to or through  one or more  Agents  pursuant  to
this  Agreement,  a Pricing  Supplement  with  respect  to such  Notes in a form
previously approved by the Agents and will file such Pricing Supplement pursuant
to Rule 424(b)(3) under the 1933 Act not later than the close of business of the
SEC on the third business day after the date on which such Pricing Supplement is
first used.

      (l) Stand-Off Agreement. If specified by the applicable Agent or Agents in
connection  with a purchase of Notes from the Company as principal,  between the
date of the  agreement  to  purchase  such  Notes and the  Settlement  Date with
respect to such  purchase,  the  Company  will not,  without  the prior  written
consent of such Agent or  Agents,  offer or sell,  grant any option for the sale
of, or enter into any  agreement  to sell,  any debt  securities  of the Company
(other  than  the  Notes  that  are to be sold  pursuant  to such  agreement  or
commercial  paper and  borrowings  under  bank  lines of credit in the  ordinary
course of business).


SECTION 5.  Conditions of Obligations.

      The  obligations  of the  Agents to  purchase  Notes  from the  Company as
principal and to solicit offers to purchase Notes as agents of the Company,  and
the  obligations of any purchaser of Notes sold through an Agent as agent,  will
be subject at all times to the accuracy of the representations and warranties on
the part of the Company  herein  contained and to the accuracy of the statements
of the Company's  officers  made in any  certificate  furnished  pursuant to the
provisions  hereof,  to the performance and observance by the Company of all its
covenants  and  agreements  herein  contained  and to the  following  additional
conditions precedent:

                                    -13-


<PAGE>


     (a)  At the date  hereof,  the Agents  shall have  received a  certificate,
          dated the date hereof,  of the Company  signed by its President or one
          of its Vice Presidents and the Treasurer or an Assistant  Treasurer of
          the Company,  substantially in the form thereof attached as Appendix I
          hereto.

     (b)  At the date hereof, the Agents shall have received opinions, dated the
          date hereof, of LeBoeuf,  Lamb, Greene & MacRae,  L.L.P.,  counsel for
          the  Company,   and  Brown  &  Wood  LLP,   counsel  for  the  Agents,
          substantially  in the forms thereof attached hereto as Appendix II and
          III,  respectively,  with  reproduced or conformed  copies thereof for
          each of the Agents.

     (c)  At the date hereof, the Agents shall have received a letter, dated the
          date hereof, from Arthur Andersen LLP, substantially to the effect set
          forth in Appendix  IV hereto,  with  reproduced  or  conformed  copies
          thereof for each of the Agents.

     (d)  At the date hereof,  Brown & Wood LLP,  counsel for the Agents,  shall
          have been  furnished  with such  documents  and  opinions  as they may
          require for the purpose of enabling them to pass upon the issuance and
          sale of the Notes and the  issuance  and delivery of the Class A Bonds
          as  herein  contemplated  and  related  proceedings,  or in  order  to
          evidence the accuracy or completeness of any of the representations or
          warranties,  or  the  fulfillment  of any  of  the  conditions  herein
          contained; and all proceedings taken by the Company in connection with
          the  issuance  and sale of the Notes and the  issuance and delivery of
          the Class A Bonds as herein contemplated shall be satisfactory in form
          and substance to the Agents and Brown & Wood LLP.


SECTION       6. Delivery of and Payment for Notes Sold through an Agent.

      Delivery  of Notes  sold  through  an Agent as agent  shall be made by the
Company to such Agent for the  account of any  purchaser  only  against  payment
therefor in immediately  available  funds.  In the event that a purchaser  shall
fail  either to accept  delivery  of or to make  payment  for a Note on the date
fixed for  settlement,  such Agent shall promptly notify the Company and deliver
such Note to the Company and, if such Agent has theretofore paid the Company for
such Note,  the Company will promptly  return such funds to such Agent.  If such
failure  occurred  for any  reason  other  than  default  by such  Agent  in the
performance of its obligations hereunder,  the Company will reimburse such Agent
on an  equitable  basis for its loss of the use of the funds for the period such
funds were credited to the

                                    -14-


<PAGE>



Company's  account  but in no event  shall the  Company be  required to pay such
Agent any commission with respect to such Note.


SECTION 7.  Subsequent Documentation Requirements of the Company.

      The Company covenants and agrees that:

      (a)  Subsequent   Delivery  of  Certificates.   Each  time  that  (i)  the
Registration Statement or the Prospectus shall be amended or supplemented (other
than by a Pricing  Supplement and other than by an amendment or supplement which
relates exclusively to the issuance and/or offering of securities other than the
Notes), (ii) there is filed with the SEC any document  incorporated by reference
into  the  Prospectus  (other  than any  Current  Report  on Form  8-K  relating
exclusively to the issuance and/or offering of securities  other than the Notes,
unless an Agent shall otherwise  specify),  or (iii) (if required by an Agent in
connection  with the purchase of Notes from the Company by one or more Agents as
principal)  the Company  sells Notes to such Agent or Agents as  principal,  the
Company  shall  furnish  or cause to be  furnished  to the  Agents  forthwith  a
certificate  dated  the  date of  filing  with  the SEC of  such  supplement  or
document, the date of effectiveness of such amendment, or the date of such sale,
as the case may be, in form  satisfactory to the Agents,  to the effect that the
statements contained in the certificate referred to in Section 5(a) hereof which
were last  furnished  to the  Agents  are true and  correct  at the time of such
amendment, supplement, filing or sale, as the case may be, as though made at and
as of such time  (except that such  statements  shall be deemed to relate to the
Registration  Statement and the Prospectus as amended and  supplemented  to such
time) or, in lieu of such  certificate,  a certificate  of the same tenor as the
certificate  referred to in said Section  5(a) hereof,  modified as necessary to
relate  to  the  Registration  Statement  and  the  Prospectus  as  amended  and
supplemented to the time of delivery of such certificate.

      (b)  Subsequent  Delivery  of  Legal  Opinions.  Each  time  that  (i) the
Registration Statement or the Prospectus shall be amended or supplemented (other
than by a Pricing Supplement or an amendment or supplement  providing solely for
the  inclusion  of  additional  financial  information,  and  other  than  by an
amendment  or  supplement  which  relates  exclusively  to an  offering  of debt
securities other than the Notes),  (ii) there is filed with the SEC any document
incorporated by reference into the Prospectus  (other than any Current Report on
Form 8-K or  Quarterly  Report on Form  10-Q,  unless an Agent  shall  otherwise
reasonably  request),  or (iii) (if required by an Agent in connection  with the
purchase  of Notes from the  Company  by one or more  Agents as  principal)  the
Company  sells Notes to such Agent or Agents as  principal,  the  Company  shall
furnish or cause to be  furnished  forthwith to the Agents and to counsel to the
Agents a written opinion of LeBoeuf,  Lamb, Greene & MacRae,  L.L.P., counsel to
the  Company,  dated  the  date of  filing  with the SEC of such  supplement  or
document, the

                                    -15-


<PAGE>



date of effectiveness  of such amendment,  or the date of such sale, as the case
may be, in form and substance  satisfactory to the Agents,  of the same tenor as
the opinion referred to in Section 5(b) hereof, but modified,  as necessary,  to
relate  to  the  Registration  Statement  and  the  Prospectus  as  amended  and
supplemented  to the  time of  delivery  of such  opinion;  or,  in lieu of such
opinion,  such counsel shall furnish the Agents with a letter  substantially  in
the form of  Appendix  V hereto to the  effect  that the Agents may rely on such
last  opinion to the same  extent as though it was dated the date of such letter
authorizing  reliance  (except that  statements  in such last  opinion  shall be
deemed to relate to the Registration Statement and the Prospectus as amended and
supplemented to the time of delivery of such letter authorizing reliance).

      (c)  Subsequent  Delivery  of  Comfort  Letters.  Each  time  that (i) the
Registration  Statement or the Prospectus  shall be amended or  supplemented  to
include additional financial  information,  (ii) there is filed with the SEC any
document incorporated by reference into the Prospectus which contains additional
financial information,  or (iii) (if required by an Agent in connection with the
purchase  of Notes from the  Company  by one or more  Agents as  principal)  the
Company  sells Notes to such Agent or Agents as  principal,  the  Company  shall
cause Arthur  Andersen LLP  forthwith to furnish the Agents a letter,  dated the
date of  filing  with  the SEC of  such  supplement  or  document,  the  date of
effectiveness  of such amendment,  or the date of such sale, as the case may be,
in form  satisfactory to the Agents, of the same tenor as the letter referred to
in Section 5(c) hereof but modified to relate to the Registration  Statement and
Prospectus as amended and supplemented to the date of such letter, and with such
changes as may be necessary to reflect  changes in the financial  statements and
other information derived from the accounting records of the Company;  provided,
however,  that if the  Registration  Statement or the  Prospectus  is amended or
supplemented  solely to  include  financial  information  as of and for a fiscal
quarter, Arthur Andersen LLP may limit the scope of such letter to the unaudited
financial  statements  included in such amendment or supplement unless any other
information  included therein of an accounting,  financial or statistical nature
is of such a nature that, in the reasonable  judgment of the Agents, such letter
should cover such other information.

      (d) Subsequent Delivery of Documents Pursuant to the Indenture.  Each time
that the Company shall deliver  documents to the Trustee  pursuant to Article IV
of the  Indenture  with  respect  to the Notes or  Article  III of the PSCo 1939
Mortgage  (as  defined in the  Indenture)  with  respect to Class A Bonds  being
issued  with  respect to the Notes,  the  Company  shall  furnish or cause to be
furnished to the Agents and to counsel to the Agents a copy of such documents.



                                    -16-


<PAGE>



SECTION 8.  Indemnification.

      (a)  Indemnification  of the Agents.  The Company  agrees to indemnify and
hold harmless each Agent and each person, if any, who controls such Agent within
the meaning of Section 15 of the 1933 Act  against  any and all losses,  claims,
damages  or  liabilities,  joint or  several,  to which  they or any of them may
become  subject  under the 1933 Act or any other  statute  or common  law and to
reimburse each such Agent and controlling person for any legal or other expenses
(including,  subject to subparagraph  (c) of this Section 8, reasonable  counsel
fees) incurred by them, as incurred, in connection with any such losses, claims,
damages or liabilities or in connection with  investigating  or preparing for or
defending  against any  litigation,  or any  investigation  or proceeding by any
governmental  agency or body,  commenced or  threatened,  or in connection  with
effecting a settlement of any such  litigation,  investigation or proceeding (if
such settlement is effected with the written consent of the Company), insofar as
such losses, claims, damages, liabilities, expenses, litigation,  investigations
or proceedings  arise out of, or are based upon, an untrue  statement or alleged
untrue statement of a material fact contained in the Registration  Statement, or
in any amendment  thereto,  or the omission or alleged  omission  therefrom of a
material fact required to be stated  therein or necessary to make the statements
therein not misleading,  or an untrue statement or alleged untrue statement of a
material fact included in the  Prospectus,  as it may have been or be amended or
supplemented,  or the omission or alleged omission  therefrom of a material fact
necessary  in  order  to  make  the  statements  therein,  in the  light  of the
circumstances  under which they were made, not  misleading;  provided,  however,
that the indemnity  agreement contained in this subparagraph (a) shall not apply
to  any  such  losses,  claims,  damages,  liabilities,   expenses,  litigation,
investigations  or  proceedings  arising out of, or based upon,  any such untrue
statement or alleged untrue statement, or any such omission or alleged omission,
if such  statement or omission was made in reliance upon and in conformity  with
information  furnished in writing to the Company by the Agents expressly for use
in the Prospectus, or any amendment or supplement thereto, or arising out of, or
based upon,  any such untrue  statement or alleged  untrue  statement in, or any
such omission or alleged  omission from, the Trustee's  Statement of Eligibility
under  the 1939 Act  filed as an  exhibit  to the  Registration  Statement;  and
provided,  further,  that the indemnity agreement contained in this subparagraph
(a) shall not inure to the  benefit  of any Agent or of any  person  controlling
such  Agent on  account of any such loss,  claim,  damage,  liability,  expense,
litigation,  investigation  or proceeding  arising from the sale of Notes to any
person if (i) such Agent  shall have  failed to send or give to such  person (A)
with or prior to the written confirmation of such sale, a copy of the Prospectus
together with any amendments or supplements thereto which shall theretofore have
been furnished to such Agent, or (B) with or prior to the delivery of such Notes
to such person,  a copy of any amendment or supplement to the  Prospectus  which
shall have been furnished to such Agent subsequent to such written  confirmation
and prior to the delivery

                                    -17-


<PAGE>



of such  Notes to such  person,  and (ii) in either  such  case,  any  untrue or
misleading  statement  or omission  made or alleged to have been made shall have
been  eliminated  or remedied in the  Prospectus  or the amendment or supplement
thereto which such Agent so failed to send or give to such person and such Agent
would  not  have  been  liable  had a copy  of  such  Prospectus,  amendment  or
supplement, as the case may be, been so sent or given to such person. Each Agent
agrees  promptly to notify the Company and each other Agent of the  commencement
of  any  litigation,  investigations  or  proceedings  against  it or  any  such
controlling person in connection with the issuance and sale of the Notes.

      (b)  Indemnification  of the Company.  Each Agent agrees to indemnify  and
hold  harmless the Company,  its  directors  and  officers,  and each person who
controls  the  Company  within the meaning of Section 15 of the 1933 Act against
any and all losses, claims,  damages or liabilities,  joint or several, to which
they or any of them may become  subject  under the 1933 Act or any other statute
or common  law and to  reimburse  each of them for any  legal or other  expenses
(including,  subject to subparagraph  (c) of this Section 8, reasonable  counsel
fees) incurred by them, as incurred, in connection with any such losses, claims,
damages or liabilities or in connection with  investigating  or preparing for or
defending  against any  litigation,  or any  investigation  or proceeding by any
governmental  agency or body,  commenced or  threatened,  or in connection  with
effecting a settlement of any such  litigation,  investigation or proceeding (if
such  settlement  is effected  with the written  consent of each Agent  affected
thereby),  insofar  as such  losses,  claims,  damages,  liabilities,  expenses,
litigations,  investigations  or  proceedings  arise out of or are based upon an
untrue  statement or alleged untrue statement of a material fact included in the
Prospectus,  or any amendment or supplement  thereto, or the omission or alleged
omission  therefrom of a material fact necessary in order to make the statements
therein,  in the light of the  circumstances  under  which they were  made,  not
misleading,  if such  statement  or omission  was made in  reliance  upon and in
conformity  with  information  furnished in writing to the Company by the Agents
expressly for use in the Prospectus, or any amendment or supplement thereto. The
Company  agrees  promptly  to  notify  the  Agents  of the  commencement  of any
litigation,  investigation  or  proceeding  against  it,  any such  director  or
officer,  or any such  controlling  person,  in connection with the issuance and
sale of the Notes.

      (c) General.  The Company and the several  Agents each agrees  that,  upon
receipt of notice of the  commencement of any action against it or any director,
officer or person  controlling the Company or any person  controlling such Agent
as  aforesaid,  in  respect of which  indemnity  may be sought on account of any
indemnity  agreement  contained  herein,  it will  promptly  give  notice of the
commencement  thereof to the party or parties  against whom  indemnity  shall be
sought  hereunder,  but the  omission  so to notify such  indemnifying  party or
parties of any such action shall not relieve such indemnifying  party or parties
from any liability which it or they may have to the indemnified

                                    -18-


<PAGE>



party otherwise than on account of such indemnity agreement. In case such notice
of any such action shall be so given, such indemnifying  party shall be entitled
to participate at its own expense in the defense, or, if it so elects, to assume
(in  conjunction  with any other  indemnifying  parties)  the  defense,  of such
action, in which event such defense shall be conducted by counsel chosen by such
indemnifying  party or parties  and  satisfactory  to the  indemnified  party or
parties who shall be defendant or defendants  in such action.  In no event shall
the  indemnifying  parties  be  liable  for fees and  expenses  of more than one
counsel (in addition to one local  counsel)  separate from their own counsel for
all  indemnified  parties  in  connection  with any one action or  separate  but
similar or  related  actions in the same  jurisdiction  arising  out of the same
general allegations or circumstances. The indemnity agreements contained in this
Section 8 shall be in addition to any liability  which the Company or the Agents
may otherwise have.


SECTION 9.  Payment of Expenses.

      The  Company  will pay all  expenses  incident to the  performance  of its
obligations under this Agreement, including:

               (a) The preparation and filing of the Registration  Statement and
          all  amendments  thereto  and the  Prospectus  and any  amendments  or
          supplements thereto;

               (b) The preparation, filing and reproduction of this Agreement;

               (c) The  preparation,  printing,  issuance  and  delivery  of the
          Notes,  including  any  fees  and  expenses  relating  to  the  use of
          book-entry notes;

               (d) The fees and  disbursements of the Company's  accountants and
          counsel,  of the Trustee and its counsel,  and of The Depository Trust
          Company;

               (e) The  reasonable  fees and  disbursements  of  counsel  to the
          Agents  incurred in connection with the  establishment  of the program
          relating  to the Notes and  incurred  from time to time in  connection
          with the transactions contemplated hereby;

               (f) The  qualification  of the Notes  under state  securities  or
          "Blue Sky" laws in  accordance  with the  provisions  of Section  4(h)
          hereof,   including   filing   fees  and  the   reasonable   fees  and
          disbursements of counsel to the Agents in connection  therewith and in
          connection  with the  preparation of any Blue Sky Survey and any Legal
          Investment  Survey,  and the  printing  and  delivery to the Agents of
          copies of any Blue Sky Survey and any Legal Investment Survey;


                                    -19-


<PAGE>



               (g) The  printing  and  delivery to the Agents in  quantities  as
          hereinabove  stated of copies of the  Registration  Statement  and any
          amendments  thereto,  and of the  Prospectus  and  any  amendments  or
          supplements  thereto, and the delivery by the Agents of the Prospectus
          and  any  amendments  or  supplements   thereto  in  connection   with
          solicitations or confirmations of sales of the Notes;

               (h) The  preparation,  printing  and  delivery  to the  Agents of
          copies of the Indenture and all supplements and amendments thereto;

               (i) Any fees  charged  by rating  agencies  for the rating of the
          Notes;

               (j) The fees and expenses incurred in connection with the listing
          of the Notes on any securities exchange;

               (k) The fees and expenses,  if any,  incurred with respect to any
          filing with the National Association of Securities Dealers, Inc.;

               (l)The  cost of  providing  any  CUSIP  or  other  identification
          numbers for the Notes; and

               (m) Any reasonable  out-of-pocket expenses incurred by the Agents
          in  connection  with this  Agreement,  provided  that the Agents  have
          notified  the Company of any such  expenses  prior to  incurring  such
          expenses.


SECTION 10.  Representations, Warranties and Agreements to
               Survive Delivery.

      All representations, warranties and agreements contained in this Agreement
or in certificates of officers of the Company submitted  pursuant hereto,  shall
remain operative and in full force and effect,  regardless of any  investigation
made by or on behalf of the Agents or any controlling  person of an Agent, or by
or on behalf of the Company,  and shall survive each delivery of and payment for
any of the Notes.


SECTION 11.  Termination.

      (a) Termination of this Agreement. This Agreement (excluding any agreement
by one or more Agents to purchase  Notes from the Company as  principal)  may be
terminated  for any  reason,  at any time by either the Company or an Agent with
respect  to such  Agent  upon the  giving  of 30 days'  written  notice  of such
termination to the other parties hereto.

      (b)   Termination of Agreement to Purchase Notes as
Principal.  An Agent or Agents may terminate any agreement by
such Agent or Agents to purchase Notes from the Company as

                                    -20-


<PAGE>



principal,  immediately  upon  notice to the  Company,  at any time prior to the
Settlement Date relating thereto, if:

              (i) (A) the  Company  shall have  failed or refused to perform any
                  covenant or agreement on its part to be performed hereunder at
                  or  prior  to  the  Settlement  Date,  or (B)  the  conditions
                  specified in Section 5 hereof shall not have been fulfilled;

             (ii) the subject  matter of the  Prospectus  or of any amendment or
                  supplement  to the  Prospectus  (other  than an  amendment  or
                  supplement  relating  solely to the activities of any Agent or
                  Agents),  in the reasonable judgment of such Agent, shall have
                  made it  impracticable  for such Agent to market the Notes, or
                  to enforce contracts for the sale of the Notes, upon the terms
                  specified in the Prospectus;

            (iii) (A) there shall have  occurred any outbreak or  escalation  of
                  hostilities  or other  national or  international  calamity or
                  crisis,  (B) trading in the Common Stock of the Company  shall
                  have  been  suspended  by the SEC or any  national  securities
                  exchange,  or trading generally on the New York Stock Exchange
                  shall have been  suspended,  or minimum or maximum  prices for
                  trading  shall have been fixed,  or maximum  ranges for prices
                  for securities shall have been required on said exchange or by
                  order of the SEC or any other  governmental  authority  having
                  jurisdiction,  or (C) a  banking  moratorium  shall  have been
                  declared by either Federal or New York State  authorities,  in
                  any such case with the result that, in the reasonable judgment
                  of such  Agent,  it shall be  impracticable  for such Agent to
                  market the Notes, or to enforce  contracts for the sale of the
                  Notes, upon the terms specified in the Prospectus; or

             (iv) the rating  assigned  by Moody's  Investors  Service,  Inc. or
                  Standard & Poor's  Ratings  Service to the Program or any debt
                  securities of the Company as of the date of such  agreement to
                  purchase  Notes from the Company as principal  shall have been
                  lowered since such date or Moody's Investors Service,  Inc. or
                  Standard & Poor's  Ratings  Service  shall have  informed  the
                  Company or publicly  announced that it has under  surveillance
                  or review, with possible negative implications,  its rating of
                  the  Program or any debt  securities  of the  Company or shall
                  have   withdrawn  its  rating  of  the  Program  or  any  debt
                  securities of the Company.

      (c) General. In the event of any such termination,  no party will have any
liability in respect of this  Agreement or such agreement to purchase Notes from
the Company as  principal,  as the case may be, to the other  parties  hereto or
thereto,

                                    -21-


<PAGE>



except  that (i) the  Agents  shall be  entitled  to any  commissions  earned in
accordance with the third paragraph of Section 3(b) hereof,  (ii) if at the time
of  termination  (a) any Agent shall own any Notes  purchased by it hereunder as
principal  with the intention of reselling  them and shall so notify the Company
or (b) an offer to  purchase  any of the Notes has been  accepted by the Company
but the time of  delivery  to the  purchaser  or his  agent of the Note or Notes
relating  thereto has not occurred,  the covenants set forth in Sections 4 and 7
hereof shall remain in effect  until such Notes are so resold or  delivered,  as
the case may be,  (iii) the  covenant  set forth in  Section  4(g)  hereof,  the
indemnity  agreement  set  forth in  Section  8 hereof,  and the  provisions  of
Sections  10,  13 and 14  hereof  shall  remain  in  effect  and  (iv)  if  such
termination is pursuant to subsection  (a),  (b)(i),  (b)(ii) or (b)(iv) of this
Section 11, the Company  shall  reimburse  the  expenses of the Agents and their
counsel to the extent provided in Section 9.


SECTION 12.  Notices.

      Unless otherwise provided herein, all notices required under the terms and
provisions  hereof shall be in writing,  either  delivered by hand,  by mail, by
telegram or by facsimile (confirmed by telephone),  and any such notice shall be
effective when received at the address specified below.


      If to the Company:

            Public Service Company of Colorado
            1225 17th Street
            Denver, Colorado  80202
            Attention:
            Facsimile:
            Telephone:

      If to the Agents:

            Merrill Lynch & Co.
            Merrill Lynch, Pierce, Fenner & Smith
                 Incorporated
            World Financial Center
            North Tower, 10th Floor
            New York, New York  10281-1310
            Attention:  MTN Product Management
            Facsimile:  (212) 449-2234
            Telephone:

            Goldman, Sachs & Co.
            85 Broad Street
            New York, New York  10004
            Attention:  Credit Control - Medium-Term Notes
            Facsimile:  (212) 357-8680
            Telephone:  (212) 902-3711


                                    -22-


<PAGE>




or at such other address as such party may designate from time to time by notice
duly given in accordance with the terms of this Section 12.


SECTION 13.  Parties.

      This  Agreement  shall  inure to the  benefit of and be binding  upon each
Agent and the Company and their  respective  successors.  Nothing  expressed  or
mentioned  in this  Agreement  is  intended  or shall be  construed  to give any
person, firm or corporation,  other than the parties hereto and their respective
successors and the controlling persons and officers and directors referred to in
Section 8 and their  heirs and  legal  representatives,  any legal or  equitable
right,  remedy or claim under or in respect of this  Agreement or any  provision
herein  contained.  This Agreement and all conditions and provisions  hereof are
intended  to be for the sole and  exclusive  benefit of the  parties  hereto and
their  respective  successors  and said  controlling  persons and  officers  and
directors and their heirs and legal  representatives,  and for the benefit of no
other person, firm or corporation. No purchaser of Notes shall be deemed to be a
successor by reason merely of such purchase.


SECTION 14.  Governing Law.

      This Agreement and all the rights and  obligations of the parties  created
hereby  shall be governed by and  construed in  accordance  with the laws of the
State of New York  applicable  to  agreements  made and to be  performed in such
State.


SECTION 15.  Counterparts.

      This  Agreement  may be  executed  in one or  more  counterparts  and,  if
executed in more than one counterpart,  the executed  counterparts  hereof shall
constitute a single instrument.



                                    -23-


<PAGE>



      If  the  foregoing  is  in  accordance  with  your  understanding  of  our
agreement, please sign and return to the Company a counterpart hereof, whereupon
this  instrument  along with all  counterparts  will become a binding  agreement
among the Agents and the Company in accordance with its terms.

                                    Very truly yours,

                                    PUBLIC SERVICE COMPANY OF COLORADO


                                    By________________________________
                                      Title:


CONFIRMED AND ACCEPTED, as of the date
  first above written:


MERRILL LYNCH, PIERCE FENNER & SMITH
            INCORPORATED



By__________________________________
  Name:
  Title:



GOLDMAN, SACHS & CO.



____________________________________
     (Goldman, Sachs & Co.)



                                    -24-


<PAGE>



                                                                       EXHIBIT A




      The  following  terms,  if  applicable,  shall be agreed to by one or more
Agents and the Company in connection with each sale of Notes:



            Principal Amount:  $________

            Interest Rate:
            Default Rate:
            Interest Payment Dates:

            If Redeemable at the option of the Company:

              Initial Redemption Date:
              Initial Redemption Percentage:
              Annual Redemption Percentage Reduction, if any:

            If Repayable at the option of Holders:

              Repayment Date(s):
              Repayment Price:

            Original Issue Date:
            Date of Maturity:
            Authorized Denomination:
            Purchase Price:  ___%, plus accrued interest, if any,
            from ____________
            Settlement Date and Time:
            Additional Terms:

      In  connection  with the purchase of Notes from the Company by one or more
Agents as principal, agreement as to whether the following will be required:

      Officer's  Certificate  pursuant  to  Section  7(a)  of  the  Distribution
        Agreement.
      Legal Opinions pursuant to Section 7(b) of the Distribution Agreement.
      Comfort Letter pursuant to Section 7(c) of the Distribution Agreement.
      Stand-off   Agreement   pursuant  to  Section  4(l)  of  the  Distribution
        Agreement.


                                    -1-


<PAGE>



                                                                      Schedule A




      As  compensation  for the  services of the Agents  hereunder,  the Company
shall pay the applicable  Agent,  on a discount basis, a commission for the sale
of each  Note  equal to the  principal  amount of such  Note  multiplied  by the
appropriate percentage set forth below:

                                                    Percent of
            Maturity Ranges                     Principal Amount
            ---------------                     ----------------

From  9 months to less than 1 year  . . . . . . .     .125%
From  1 year to less than 18 months . . . . . . .     .150%
From  18 months to less than 2 years  . . . . . .     .200%
From  2 years to less than 3 years  . . . . . . .     .250%
From  3 years to less than 4 years  . . . . . . .     .350%
From  4 years to less than 5 years  . . . . . . .     .450%
From  5 years to less than 6 years  . . . . . . .     .500%
From  6 years to less than 7 years  . . . . . . .     .550%
From  7 years to less than 10 years . . . . . . .     .600%
From  10 years to less than 15 years  . . . . . .     .625%
From  15 years to less than 20 years  . . . . . .     .700%
From  20 years to 30 years  . . . . . . . . . . .     .750%












                                    -1-


<PAGE>



                                                                      APPENDIX I




                         FORM OF OFFICER'S CERTIFICATE
                         -----------------------------

                      PUBLIC SERVICE COMPANY OF COLORADO


      We, [authorized  officers' names],  [the President] [a Vice President] and
[the Treasurer] [an Assistant Treasurer] respectively, of Public Service Company
of Colorado, a Colorado corporation (the "Company"), pursuant to Section 5(a) of
the Distribution  Agreement dated  _____________ (the "Distribution  Agreement")
among  the  Company  and  [Agents],  hereby  certify  that,  to the  best of our
knowledge, after reasonable investigation:

     1.  Since  the  respective  dates as of which  information  is given in the
Registration  Statement  and  Prospectus  (as  such  terms  are  defined  in the
Distribution  Agreement),  except as otherwise  stated  therein or  contemplated
thereby,  [or since [insert date of applicable agreement by an Agent to purchase
Notes from the Company as principal]],  there has not been any material  adverse
change in the business,  property or condition,  financial or otherwise,  of the
Company  and its  subsidiaries  considered  as one  enterprise,  whether  or not
arising in the ordinary course of business;

     2. The representations and warranties of the Company contained in Section 2
of the  Distribution  Agreement  are true and  correct  with the same  force and
effect as though expressly made at and as of the date hereof;

     3. The Company has performed or complied with all  agreements and satisfied
all  conditions on its part to be performed or satisfied at or prior to the date
hereof; and

     4. No stop order suspending the effectiveness of the Registration Statement
has been  issued  and no  proceeding  for that  purpose  has been  initiated  or
threatened by the Securities and Exchange Commission.



                                       I-1


<PAGE>



      IN WITNESS WHEREOF, we have hereunto signed our names and affixed the seal
of the Company.

Dated:  _____________, ____
                                          ________________________________
                                          [Title]
[SEAL]

                                          ________________________________
                                          [Title]


                                       I-2
<PAGE>

                                                                   Appendix II
                                                                       to
                                                                  Distribution
                                                                    Agreement

            [LETTERHEAD OF LEBOEUF, LAMB, GREENE & MACRAE, L.L.P.]


[Agents]
Ladies and Gentlemen:

      We have acted as  counsel  to Public  Service  Company  of  Colorado  (the
"Company")  in  connection  with the sale by the  Company of up to  $250,000,000
aggregate  principal amount of its Secured  Medium-Term Notes, Series B (being a
series of First  Collateral  Trust Bonds) (the  "Notes"),  which are  registered
pursuant to the  registration  statement (File No.  333-____) of the Company for
the registration  under the Securities Act of 1933, as amended (the "1933 Act"),
of up to  $400,000,000  in aggregate  principal  amount of its First  Collateral
Trust  bonds,  including  the  Notes.  This  opinion is being  delivered  to you
pursuant to Section  5(b) of the  Distribution  Agreement,  dated  _______  (the
"Agreement"),  between the Company and the several  agents  named  therein  (the
"Agents").  Unless  otherwise  stated,  defined terms used herein shall have the
respective meanings given them in the Agreement.

      We are not general  counsel to the Company and our  representation  of the
Company consists of advising it with respect to corporate and regulatory matters
as to which we have been specifically  consulted. We are familiar with the legal
matters  pertaining to, and the corporate  proceedings of the Company taken with
respect to, the  authorization  of the  issuance  and sale by the Company of the
Notes and the  authorization  of the issuance and delivery of the Class A Bonds.
We have  examined,  among  other  things,  the  Registration  Statement  and the
Prospectus,  and any amendment or supplement  thereto,  the corporate records of
the Company, the Indenture,  the Supplemental  Indenture creating the Notes, the
PSCO  1939  Mortgage  and  the   supplemental   indenture   thereto  (the  "1939
Supplemental  Mortgage")  under  which the Class A Bonds are being  issued,  the
proceedings before The Public Utilities Commission of the State of Colorado with
respect to the  issuance  and sale of the Notes and the issuance and delivery of
the Class A Bonds and such other  proceedings,  papers and  documents as we have
deemed relevant for the purpose of rendering the opinions  enumerated  below. In
such  examination,  we have  assumed  the  genuineness  of all  signatures,  the
authenticity  of all documents  submitted to us as originals,  the conformity to
the  original  documents  of all  documents  submitted  to us as copies  and the
authenticity  of all  such  latter  documents.  We  have  relied  as to  various
questions of fact upon  discussions  with  officers and  representatives  of the
Company and the  representations  and warranties of the Company contained in the
Agreement and upon the  certificates of public  officials and of officers of the
Company  being  delivered  to you  thereunder.  With  respect  to  the  opinions
expressed  in  paragraphs  (xii),  (xiii)  and (xiv)  below,  we have  relied on
information obtained from public records and from the Company.

      On the  basis  of the  foregoing,  and  subject  to  the  limitations  and
qualifications set forth herein, it is our opinion that:

     (i)  The Company has been duly  incorporated  and is validly  existing as a
          corporation  in good standing  under the laws of the State of Colorado
          with  corporate  power and  authority  to own,  lease and  operate its
          properties and to conduct its business as described in the Prospectus,
          as amended or supplemented to the date hereof.

     (ii) To the best of our  knowledge,  the  Company  is duly  qualified  as a
          foreign  corporation  to transact  business and is in good standing in
          each jurisdiction in which such qualification is required,  whether by
          reason of the  ownership  or leasing  of  property  or the  conduct of
          business,  except  where  the  failure  to so  qualify  or be in  good
          standing  would not have a material  adverse  effect on the  business,
          properties  or   operations  of  the  Company  and  its   subsidiaries
          considered as one enterprise.


                                    B-1

<PAGE>



     (iii)Each Significant  Subsidiary of the Company (as defined in Rule 405(c)
          of   Regulation  C  under  the  1933  Act),  if  any,  has  been  duly
          incorporated and is validly existing as a corporation in good standing
          under the laws of the jurisdiction of its incorporation, has corporate
          power and  authority  to own,  lease and  operate its  properties  and
          conduct its business as described in the  Registration  Statement  and
          the Prospectus, as amended or supplemented to the date hereof, and, to
          the best of our knowledge,  is duly qualified as a foreign corporation
          to transact  business and is in good standing in each  jurisdiction in
          which  such  qualification  is  required,  whether  by  reason  of the
          ownership  or leasing of property or the conduct of  business,  except
          where the failure to so qualify or be in good standing  would not have
          a material adverse effect on the business, properties or operations of
          the Company and its subsidiaries considered as one enterprise.

     (iv) To the best of our  knowledge,  the Company is not in violation of its
          charter or by-laws or in default in the  performance  or observance of
          any material obligation, agreement, covenant or condition contained in
          any contract,  indenture,  mortgage,  loan agreement,  note,  lease or
          other  instrument  to which it is a party or by which it or any of its
          properties may be bound.  The execution and delivery of the Agreement,
          the Supplemental  Indenture,  the 1939  Supplemental  Mortgage and the
          consummation  of  the  transactions   contemplated   therein  and  the
          incurrence  of the  obligations  therein  contained  will not conflict
          with,  or  constitute  a breach of, or default  under,  or (other than
          under the Indenture and the 1939  Mortgage)  result in the creation or
          imposition  of any lien,  charge or  encumbrance  upon any property or
          assets of the Company pursuant to, any contract, indenture,  mortgage,
          loan agreement,  note,  lease or other  instrument  known to us and to
          which the  Company  is a party or by which it may be bound or to which
          any of its property or assets is subject,  or any law,  administrative
          regulation or  administrative  or court order or decree known to us to
          be  applicable  to the  Company of any court or  governmental  agency,
          authority  or body or any  arbitrator  having  jurisdiction  over  the
          Company;  nor  will  such  action  result  in  any  violation  of  the
          provisions of the charter or by-laws of the Company.

     (v)  The  Indenture  has been duly and  validly  authorized,  executed  and
          delivered  by the Company and is in due and proper form and  (assuming
          the Indenture has been duly authorized,  executed and delivered by the
          Trustee)  constitutes  a legal,  valid  and  binding  mortgage  of the
          Company,   enforceable  in  accordance  with  its  terms,   except  as
          enforcement  thereof may be limited by laws and  principles  of equity
          affecting   generally  the   enforcement  of  mortgagees'   and  other
          creditors'  rights,   including  without  limitation   bankruptcy  and
          insolvency laws and state laws which affect the enforcement of certain
          remedial  provisions of the Indenture;  provided,  however,  that such
          state laws will not, in our opinion,  render the remedies  afforded by
          the Indenture inadequate for the practical  realization of the benefit
          of the security provided thereby.

     (vi) The Indenture is qualified  under the Trust  Indenture Act of 1939, as
          amended.

    (vii) The Notes are in due and proper form and the  issuance and sale of the
          Notes have been duly authorized by all necessary corporate action, and
          when a Note has been duly executed and  authenticated  as specified in
          the Indenture and the Company Order and Officer's Certificate (each as
          defined  in the  Indenture)  applicable  to such  Note  and  delivered
          against payment of the consideration therefor determined in accordance
          with the  Agreement,  such  Note will be a legal,  valid  and  binding
          obligation of the Company  enforceable  (subject to the exceptions and
          limitations  referred to in paragraph (v) hereof) in  accordance  with
          its terms and entitled to the benefits and security of the  Indenture;
          and,   assuming  that  the   Supplemental   Indenture  has  been  duly
          transmitted to the appropriate public officials for recording and will
          be duly recorded,  such Note will be secured  equally and ratably with
          all other Notes and bonds outstanding under the Indenture.

   (viii) The PSCO 1939 Mortgage has been duly and validly authorized, executed
          and  delivered  by the  Company  and is in due  and  proper  form  and
          (assuming  the PSCO 1939 Mortgage has been duly  authorized,  executed
          and delivered by the trustee  thereunder)  constitutes a legal,  valid
          and binding  mortgage of the Company,  enforceable in accordance  with
          its terms,  except as  enforcement  thereof may be limited by laws and
          principles  of  equity   affecting   generally  the   enforcement   of
          mortgagees'

                                    B-2

<PAGE>



          and other creditors' rights,  including without limitation  bankruptcy
          and  insolvency  laws and state laws which affect the  enforcement  of
          certain  remedial  provisions  of the PSCO  1939  Mortgage;  provided,
          however,  that such state laws will not,  in our  opinion,  render the
          remedies  afforded  by the  PSCO  1939  Mortgage  inadequate  for  the
          practical realization of the benefit of the security provided thereby.

     (ix) The  Class A Bonds are in due and  proper  form and the  issuance  and
          delivery  of the  Class A  Bonds  have  been  duly  authorized  by all
          necessary  corporate action; and when (a) a Class A Bond has been duly
          executed,  authenticated  and delivered to the Trustee as specified in
          the PSCO 1939  Mortgage  and the order of an  officer  of the  Company
          applicable to such Class A Bond and (b) the related Note has been duly
          executed  and  authenticated  as specified  in the  Indenture  and the
          Company  Order and Officer's  Certificate  applicable to such Note and
          delivered against payment of the consideration  therefor determined in
          accordance  with the  Agreement,  such  Class A Bond  will be a legal,
          valid and binding  obligation of the Company  enforceable  (subject to
          the exceptions and limitations referred to in paragraph (viii) hereof)
          in accordance with its terms and entitled to the benefits and security
          of the PSCO 1939 Mortgage;  and,  assuming that the 1939  Supplemental
          Mortgage has been duly transmitted to the appropriate public officials
          for  recording  and will be duly  recorded,  such Class A Bond will be
          secured equally and ratably with all other bonds outstanding under the
          PSCO  1939   Mortgage   (except  to  the  extent  that  any   sinking,
          amortization, improvement or other fund may afford additional security
          for such bonds of any particular series).

     (x)  The Agreement has been duly authorized,  executed and delivered by the
          Company.

     (xi) The issuance  and sale of the Notes,  and the issuance and delivery of
          the Class A Bonds,  have been duly authorized and approved by an order
          of The Public  Utilities  Commission of the State of Colorado and such
          order is final and in full  force and effect on the date  hereof,  the
          time for  appeal  therefrom  or review  thereof or  intervention  with
          respect thereto having expired;  no further  approval,  authorization,
          consent or other  order of any  public  board or body  (other  than in
          connection or compliance with the provisions of the securities laws of
          any jurisdiction) is legally required for the issuance and sale by the
          Company of the Notes pursuant to the Agreement or for the issuance and
          delivery  of the Class A Bonds;  and the Company is  presently  exempt
          from all of the provisions of the Public Utility  Holding  Company Act
          of 1935, as amended, except Section 9(a)(2) thereof.

     xii) The  Company  has good title to the real  properties  specifically  or
          generally  described or referred to in the  Indenture  and in the PSCO
          1939 Mortgage as subject to the respective  liens thereof (except such
          real property as may have been sold,  exchanged or otherwise  disposed
          of), subject only to (a) in the case of all such properties,  the lien
          of the PSCO 1939 Mortgage and "permitted  encumbrances" (as defined in
          the PSCO 1939 Mortgage) and (b) in the case of such  properties  which
          are used or to be used in or in connection  with the Electric  Utility
          Business  (as  defined in the  Indenture)  (whether or not such is the
          sole use of such  property)  the lien of the  Indenture  and Permitted
          Liens (as defined in the Indenture).

   (xiii) The Indenture   constitutes  a   mortgage   lien  on  the   properties
          specifically or generally  described or referred to therein as subject
          to the lien  thereof  (except such  properties  as may have been sold,
          exchanged or otherwise  disposed of or released  from the lien thereof
          in accordance  with the terms  thereof),  subject to no liens prior to
          the lien of the Indenture  other than Permitted  Liens and the lien of
          the PSCO 1939  Mortgage;  and the  Indenture by its terms  effectively
          subjects to the lien  thereof  all  property  (except  property of the
          kinds  specifically  excepted  from the lien of the  Indenture  by the
          terms thereof) acquired by the Company after the date of execution and
          delivery of the  Indenture  and used or to be used in or in connection
          with the Electric  Utility  Business,  subject to Permitted Liens, the
          lien of the PSCO 1939 Mortgage,  any lien thereon existing at the time
          of such  acquisition  and to any  liens  for  unpaid  portions  of the
          purchase  money placed  thereon at the time of such  acquisition,  and
          also subject to the provisions of Article Thirteen of the

                                    B-3

<PAGE>



          Indenture  and to certain  possible  claims of a trustee in bankruptcy
          and possible claims and taxes of the federal government.

    (xiv) The  PSCO  1939  Mortgage  constitutes  a first  mortgage  lien on the
          properties  specifically or generally described or referred to therein
          as subject to the lien thereof,  including the shares of stock pledged
          thereunder  (except such property as may have been sold,  exchanged or
          otherwise  disposed of or released from the lien thereof in accordance
          with the terms thereof),  subject to no liens prior to the lien of the
          PSCO 1939 Mortgage other than "permitted  encumbrances";  and the PSCO
          1939  Mortgage by its terms  effectively  subjects to the lien thereof
          all property (except property of the kinds specifically  excepted from
          the lien of the PSCO 1939 Mortgage by the terms  thereof)  acquired by
          the Company  after the date of the  execution and delivery of the PSCO
          1939  Mortgage,  subject  to  "permitted  encumbrances",  to any  lien
          thereon  existing at the time of such acquisition and to any liens for
          unpaid  portions of the purchase  money placed  thereon at the time of
          such acquisition,  and also subject to the provisions of Article XI of
          the PSCO 1939 Mortgage and to certain  possible claims of a trustee in
          bankruptcy and possible claims and taxes of the federal government.

     (xv) The facsimile  signature of a Senior Vice  President or Vice President
          of the  Company in lieu of his manual  signature  on the Notes and the
          Class A Bonds  and the  facsimile  signature  of the  Secretary  or an
          Assistant  Secretary of the Company  attesting the  corporate  seal in
          lieu of his manual  signature  on the Notes and the Class A Bonds have
          been duly and  properly  authorized  by the Board of  Directors of the
          Company,  are not  inconsistent  with the  provisions  of the Restated
          Articles of Incorporation,  as amended,  or By-Laws of the Company and
          are valid and effective  under the laws of the State of Colorado;  and
          the facsimile signatures of such officers on the Notes and the Class A
          Bonds have the same legal  effect as though they had  manually  signed
          and  attested  the  Notes  and the  Class A Bonds  as such  respective
          officers.

    (xvi) The  statements  in the  Company's  Annual Report on Form 10-K for the
          fiscal year ended  December 31, 1995,  incorporated  by reference into
          the  Prospectus,   under  the  headings  "Regulation  and  Rates"  and
          "Franchises"  in Item 1. BUSINESS and under the heading  "Character of
          Ownership"  in  Item  2.   Properties,   and  the  statements  in  the
          Prospectus, and any amendment or supplement thereto, under the caption
          "Security"  under  "Description of the New Bonds" and  "Description of
          the 1939  Mortgage,"  insofar as they are, or refer to,  statements of
          law or legal conclusions, have been prepared or reviewed by us and are
          correct in all material  respects and fairly  present the  information
          purported to be given. The Notes, the Indenture, the Class A Bonds and
          the PSCO 1939 Mortgage conform as to legal matters to the descriptions
          thereof  contained in the  Registration  Statement and Prospectus,  as
          amended or supplemented to the date hereof.

   (xvii) [Except  to  the  extent  set  forth  in the  next  sentence  of  this
          paragraph  (xvii),]  the  franchises  held  by  the  Company  and  its
          subsidiaries, together with the applicable Certificates of Convenience
          and Necessity issued by The Public  Utilities  Commission of the State
          of Colorado and the Public  Service  Commission  of Wyoming,  give the
          Company  and  such  subsidiaries  all  necessary   authority  for  the
          maintenance and operation of their respective  properties and business
          as now  conducted,  and  are  free  from  burdensome  restrictions  or
          conditions of an unusual character.  [As disclosed in the Incorporated
          Documents, the Company is currently providing gas and electric service
          to one  previously  franchised  municipality  while a new franchise is
          being negotiated.]

  (xviii) The  descriptions in the Registration  Statement and  the  Prospectus,
          as amended or supplemented to the date hereof, of statutes,  legal and
          governmental   proceedings  and  contracts  and  other  documents  are
          accurate in all material  respects and fairly present the  information
          purported to be given.

    (xix) The Registration Statement is effective under the 1933 Act and, to the
          best of our  knowledge,  no  proceedings  for a stop  order  have been
          instituted or are pending or threatened under Section 8(d) of the 1933
          Act; and, at the time the Registration  Statement became effective and
          at the date of

                                    B-4

<PAGE>



          the Agreement,  the Registration Statement complied,  and, at the date
          hereof,  the Prospectus,  as it may have been amended or supplemented,
          complies, as to form in all material respects with the requirements of
          the 1933 Act and the applicable  instructions,  rules and  regulations
          thereunder,  or pursuant to said  instructions,  rules and regulations
          are deemed to have complied or to comply therewith, although we do not
          express  any opinion as to the  financial  statements  (including  the
          notes  thereto) or other  financial or  statistical  data  included or
          incorporated by reference therein.

      We do not  know  of any  legal  or  governmental  proceeding  (pending  or
threatened)  required  to be  described  in the  Registration  Statement  or the
Prospectus,  as  amended  or  supplemented  to the  date  hereof,  which  is not
described as required,  nor of any contract or document of a character  required
to be described in the Registration  Statement or the Prospectus,  as amended or
supplemented  to the  hereof,  or to be filed as an exhibit to the  Registration
Statement which is not described or filed as required.

      In connection with this opinion,  we have participated in discussions with
officers  and   representatives  of  the  Company,  in  certain  of  which  your
representatives  and counsel also  participated  and at which the affairs of the
Company and the contents of the  Registration  Statement and the Prospectus were
discussed.  There is no  assurance  that all possible  material  facts as to the
Company  were  disclosed to us or that our  familiarity  with the Company or the
operations  in which it is engaged is such that we have  necessarily  recognized
the materiality of such facts as were  disclosed,  and we have to a large extent
relied upon statements of officers and  representatives of the Company as to the
significance  of those facts disclosed to us. We are not passing upon and do not
assume any  responsibility  for the  accuracy,  completeness  or fairness of the
statements contained in the Registration  Statement and the Prospectus except to
the limited extent referred to in paragraphs (xvi) and (xviii) above. Subject to
the foregoing, and to the other limitations and qualifications expressed in this
letter,  we may state that nothing has come to our attention  that would lead us
to believe that the Registration Statement,  when it became effective [or, if an
amendment to the  Registration  Statement  or an Annual  Report on Form 10-K has
been filed by the Company with the SEC  subsequent to the  effectiveness  of the
Registration  Statement,  then at the time such amendment became effective or at
the time of the most recent such filing,  as the case may be,] or at the date of
the  Agreement,  contained an untrue  statement of a material fact or omitted to
state a material  fact  required to be stated  therein or  necessary to make the
statements  therein not  misleading,  or that the  Prospectus at the date of the
Agreement  or at the date  hereof,  [or,  if the opinion is being  delivered  in
connection  with the purchase of Notes from the Company by one or more Agents as
principal  pursuant  to  Section  7(b)  of the  Agreement,  at the  date  of any
agreement  by such Agent or Agents to  purchase  Notes as  principal  and at the
Settlement Date with respect thereto,  as the case may be,] included or includes
an untrue statement of a material fact or omitted, or omits, to state a material
fact  necessary  in order to make the  statements  therein,  in the light of the
circumstances under which they were made, not misleading;  provided,  that we do
not  express  any belief as to the  financial  statements  (including  the notes
thereto) or other  financial or statistical  data contained or  incorporated  by
reference in the Registration  Statement or the Prospectus,  or any amendment or
supplement  thereto,  as to any information  contained  therein furnished to the
Company in writing by any Agent expressly for use therein or as to the Statement
of Eligibility.

      This opinion is limited to the laws of the State of New York and the State
of Colorado and the federal law of the United States of America. In addition, we
are not opining  herein with respect to the securities or "blue sky" laws of any
state.  Finally,  this opinion  speaks as of the date hereof and we undertake no
responsibility  to  advise  you of any  change in  circumstances  after the date
hereof.

      First Trust of New York, National Association is hereby authorized to rely
upon this  letter as if this letter were  addressed  to it.  Brown & Wood LLP is
hereby  authorized to rely upon this letter as to matters governed by the law of
the State of Colorado as if this letter were  addressed to them.  This letter is
not being  delivered  for the  benefit  of,  nor may it be relied  upon by,  the
holders  of the  Notes  or any  other  party  to  which  it is not  specifically
addressed or to which reliance has not expressly been permitted hereby.

                                                               Very truly yours,



                                    B-5

<PAGE>



                                                                  Appendix III
                                                                       to
                                                                  Distribution
                                                                    Agreement


                       [LETTERHEAD OF BROWN & WOOD LLP]
                    Re:  Public Service Company of Colorado



[Agents]
Ladies and Gentlemen:

      We  have  acted  as your  counsel  in  connection  with  the  transactions
contemplated  by  the  Distribution   Agreement,   dated   ______________   (the
"Agreement"),  between you and Public  Service  Company of Colorado,  a Colorado
corporation  (the  "Company"),  in connection  with the issuance and sale by the
Company  of up  to  $250,000,000  aggregate  principal  amount  of  its  Secured
Medium-Term  Notes,  Series B (being a series of First  Collateral  Trust Bonds)
(the "Notes"), being issued under its Indenture, dated as of October 1, 1993, to
First Trust of New York,  National  Association,  as successor trustee to Morgan
Guaranty  Trust  Company of New York  (formerly  Guaranty  Trust  Company of New
York),  and all  indentures  supplemental  thereto,  including the  Supplemental
Indenture  dated as of November 1, 1996  creating  the Notes (the  "Supplemental
Indenture")  (said  Indenture  dated as of  October  1, 1993 and all  indentures
supplemental  thereto  being  hereinafter   collectively   referred  to  as  the
"Indenture").

      We have  examined  such  documents  and records as we deemed  appropriate,
including the following:

     (1)  copy,  certified by the Secretary of State of the State of Colorado to
          be  a  true  and  complete   copy,   of  the   Restated   Articles  of
          Incorporation,  as amended,  and the  Certificate of Correction of the
          Company  as on file in the  office  of the  Secretary  of State of the
          State of Colorado;

     (2)  certificate  of recent date of the  Secretary of State of the State of
          Colorado to the effect that the Company is in good standing;

     (3)  copy,  certified by an Assistant Secretary of the Company to be a true
          and correct copy, of the By-Laws of the Company;

     (4)  minute book records of the Company as furnished to us by the Company;

     (5)  executed counterpart of the Agreement;

     (6)  executed counterpart of the Indenture;

     (7)  copies of papers  delivered  by the Company to the  Trustee  under the
          Indenture in connection with the authentication and delivery from time
          to time of the Notes;

     (8)  a specimen Note in definitive fully  registered form,  certified by an
          Assistant Secretary of the Company to be a true and correct specimen;

     (9)  executed counterparts of the Company's Indenture, dated as of December
          1, 1939 (the  "Original  PSCO 1939  Mortgage"),  to First Trust of New
          York,  National  Association,  as successor trustee to Morgan Guaranty
          Trust  Company of New York  (formerly  Guaranty  Trust  Company of New
          York),  and  all  indentures   supplemental  thereto,   including  the
          supplemental  indenture  dated as of  November 1, 1996 (the "PSCO 1939
          Mortgage   Supplemental   Indenture")  creating  the  Company's  first
          mortgage bonds to be made the basis of the authentication and delivery
          of the Notes (the

                                    C-1

<PAGE>



          "Class A Bonds") (the Original  PSCO 1939 Mortgage and all  indentures
          supplemental   thereto  being   hereinafter   called  the  "PSCO  1939
          Mortgage");

     (10) copies of papers  delivered  by the Company to the  trustee  under the
          PSCO 1939 Mortgage in connection with the  authentication and delivery
          of the Class A Bonds;

     (11) a specimen Class A Bond in definitive fully registered form, certified
          by an  Assistant  Secretary  of the  Company to be a true and  correct
          specimen;

     (12) copies,  certified by an Assistant Secretary of the Company to be true
          and correct  copies,  of certain  resolutions  adopted by the Board of
          Directors of the Company [and by the Executive  Committee of the Board
          of Directors of the Company] relating to the authorization,  execution
          and  delivery  of  the  Supplemental  Indenture,   the  authorization,
          execution  and  delivery  of  the  PSCO  1939  Mortgage   Supplemental
          Indenture, with respect to the authorization, issuance and sale of the
          Notes, including the Agreement, and with respect to the authorization,
          issuance and delivery of the Class A Bonds;

     (13) executed  copies of the Company's  registration  statement on Form S-3
          (Registration  File  No.  333-_____)  filed  by the  Company  with the
          Securities and Exchange Commission (the "Commission")  pursuant to the
          Securities  Act of 1933, as amended (the "1933 Act"),  relating to the
          registration  thereunder  of first  collateral  trust bonds  having an
          aggregate principal amount not exceeding  $400,000,000,  including the
          Notes.  The terms  "Registration  Statement" and "Prospectus" are used
          herein with the meanings ascribed thereto in the Agreement;

     (14) evidence of the effectiveness of the Registration  Statement under the
          1933 Act; and

     (15) a copy,  certified by the Secretary of The Public Utilities Commission
          of the State of Colorado (the "Colorado  Commission") to be a true and
          complete  copy,  of the Decision and Order of the Colorado  Commission
          adopted October 16, 1996, which authorizes the issuance and sale of up
          to  $650,000,000  aggregate  principal  amount of the Company's  first
          collateral  trust bonds,  including the Notes,  and the same principal
          amount of Class A Bonds.

            In rendering our opinion,  we have assumed,  without any independent
      investigation or verification, the authenticity of all documents submitted
      to us as  originals  and  the  conformity  to  original  documents  of all
      documents  submitted to us as certified,  conformed or photostatic copies,
      and the authenticity of all such latter documents.

            Based upon the foregoing,  and subject to the  assumptions set forth
      herein, we are of the opinion that:

          (a)  The Company has been duly incorporated and is validly existing as
               a  corporation  in good  standing  under the laws of the State of
               Colorado with  corporate  power and  authority to own,  lease and
               operate its  properties  and to conduct its business as described
               in the Prospectus, as amended or supplemented to the date hereof.

          (b)  The Indenture has been duly and validly authorized,  executed and
               delivered by the Company and  (assuming  the  Indenture  has been
               duly   authorized,   executed  and   delivered  by  the  Trustee)
               constitutes a legal,  valid and binding  mortgage of the Company,
               enforceable in accordance  with its terms,  except as enforcement
               thereof may be limited by laws and principles of equity affecting
               generally the  enforcement  of mortgagees'  and other  creditors'
               rights,  including without  limitation  bankruptcy and insolvency
               laws and state  laws  which  affect  the  enforcement  of certain
               remedial provisions of the Indenture.

          (c)  The Indenture is qualified under the Trust Indenture Act of 1939,
               as amended.


                                    C-2

<PAGE>



          (d)  The Notes are in due and proper form and the issuance and sale of
               the  Notes  by the  Company  have  been  duly  authorized  by all
               necessary  corporate  action,  and  when a  Note  has  been  duly
               executed and  authenticated as specified in the Indenture and the
               Company Order and Officer's  Certificate  (each as defined in the
               Indenture)  applicable to such Note and delivered against payment
               of the consideration  therefor  determined in accordance with the
               Agreement,   such  Note  will  be  a  legal,  valid  and  binding
               obligation of the Company enforceable  (subject to the exceptions
               and   limitations   referred  to  in  paragraph  (b)  hereof)  in
               accordance  with its  terms  and  entitled  to the  benefits  and
               security of the Indenture;  and such Note will be secured equally
               and ratably with all other Notes and bonds  outstanding under the
               Indenture.

          (e)  The PSCO  1939  Mortgage  has been duly and  validly  authorized,
               executed and delivered by the Company and (assuming the PSCO 1939
               Mortgage has been duly authorized,  executed and delivered by the
               trustee  thereunder)  constitutes  a  legal,  valid  and  binding
               mortgage  of the  Company,  enforceable  in  accordance  with its
               terms,  except as enforcement  thereof may be limited by laws and
               principles  of equity  affecting  generally  the  enforcement  of
               mortgagees'  and  other  creditors'  rights,   including  without
               limitation  bankruptcy and  insolvency  laws and state laws which
               affect the enforcement of certain remedial provisions of the PSCO
               1939 Mortgage.

          (f)  The Class A Bonds are in due and proper form and the issuance and
               delivery  of the  Class A Bonds by the  Company  have  been  duly
               authorized  by all  necessary  corporate  action;  and when (a) a
               Class A Bond has been duly executed,  authenticated and delivered
               to the Trustee as  specified  in the PSCO 1939  Mortgage  and the
               order of an officer  of the  Company  applicable  to such Class A
               Bond  and (b)  the  related  Note  has  been  duly  executed  and
               authenticated as specified in the Indenture and the Company Order
               and Officer's  Certificate  applicable to such Note and delivered
               against  payment  of the  consideration  therefor  determined  in
               accordance with the Agreement, such Class A Bond will be a legal,
               valid and binding obligation of the Company enforceable  (subject
               to the  exceptions and  limitations  referred to in paragraph (e)
               hereof) in accordance with its terms and entitled to the benefits
               and  security  of the PSCO 1939  Mortgage;  and such Class A Bond
               will  be  secured  equally  and  ratably  with  all  other  bonds
               outstanding  under the PSCO 1939  Mortgage  (except to the extent
               that any  sinking,  amortization,  improvement  or other fund may
               afford  additional  security  for such  bonds  of any  particular
               series).

          (g)  The Agreement has been duly authorized, executed and delivered by
               the Company.

          (h)  The issuance and sale of the Notes, and the issuance and delivery
               of the Class A Bonds,  have been duly  authorized and approved by
               the  Colorado  Commission;  no further  approval,  authorization,
               consent or other order of any public board or body (other than in
               connection or compliance  with the  provisions of the  securities
               laws of any  jurisdiction)  is legally  required for the issuance
               and sale by the Company of the Notes pursuant to the Agreement or
               for the  issuance  and  delivery  of the  Class A Bonds;  and the
               Company is  presently  exempt from all of the  provisions  of the
               Public Utility  Holding  Company Act of 1935, as amended,  except
               Section 9(a)(2) thereof.

          (i)  The  Notes,  the  Indenture,  the Class A Bonds and the PSCO 1939
               Mortgage  conform as to legal matters to the  description  of the
               terms  thereof  contained in the  Registration  Statement and the
               Prospectus, as amended or supplemented to the date hereof.

          (j)  The  Registration  Statement is effective under the 1933 Act and,
               to the best of our  knowledge,  no  proceedings  for a stop order
               have been  instituted or are pending or threatened  under Section
               8(d) of the 1933 Act; and, at the time the Registration Statement
               became   effective  and  at  the  date  of  the  Agreement,   the
               Registration Statement complied,

                                    C-3

<PAGE>



               and,  at the date  hereof,  the  Prospectus,  as it may have been
               amended or  supplemented,  complies,  as to form in all  material
               respects with the requirements of the 1933 Act and the applicable
               instructions,  rules and regulations  thereunder,  or pursuant to
               said  instructions,  rules  and  regulations  are  deemed to have
               complied or to comply  therewith,  although we do not express any
               opinion  as to the  financial  statements  (including  the  notes
               thereto)  or other  financial  or  statistical  data  included or
               incorporated by reference therein.

      We  have  endeavored  to see  that  the  Registration  Statement  and  the
Prospectus,  and any amendment or supplement  thereto,  comply with the 1933 Act
and  the  rules  and  regulations  of  the  Commission  thereunder  relating  to
registration  statements  on Form  S-3  and  related  prospectuses,  but we have
participated  to a  limited  extent  only in the  preparation  of the  documents
incorporated  by reference in the  Registration  Statement and Prospectus and we
cannot,  of  course,  make  any  representation  to you as to  the  accuracy  or
completeness  of statements of fact contained in the  Registration  Statement or
Prospectus,  including the documents incorporated therein by reference. Nothing,
however,  has come to our  attention  that  would  lead us to  believe  that the
Registration  Statement, at the time it became effective [or, if an amendment to
the  Registration  Statement or an Annual  Report on Form 10-K has been filed by
the  Company  with  the  Commission  subsequent  to  the  effectiveness  of  the
Registration  Statement,  then at the time such amendment became effective or at
the time of the most recent such  filing,  as the case may be] or at the date of
the  Agreement,  contained an untrue  statement of a material fact or omitted to
state a material  fact  required to be stated  therein or  necessary to make the
statements  therein not  misleading  or that the  Prospectus  at the date of the
Agreement  or at the date  hereof  [or,  if the  opinion is being  delivered  in
connection  with the purchase of Notes from the Company by one or more Agents as
principal  pursuant  to  Section  7(b)  of the  Agreement,  at the  date  of any
agreement  by such Agent or Agents to  purchase  Notes as  principal  and at the
Settlement Date with respect thereto,  as the case may be], included or includes
an untrue  statement of a material  fact or omitted or omits to state a material
fact  necessary  in order to make the  statements  therein,  in the light of the
circumstances  under which they were made, not  misleading;  provided that we do
not express any belief as to the  financial  statements  or other  financial  or
statistical  data  contained or  incorporated  by reference in the  Registration
Statement or the Prospectus,  or any amendment or supplement  thereto,  or as to
the Statement of Eligibility.

      In giving  this  opinion  we have  relied as to all  matters  governed  by
Colorado law upon the opinion of even date herewith  rendered to you by LeBoeuf,
Lamb, Greene & MacRae,  L.L.P. relating to the Notes. We express no opinion upon
matters regarding titles to properties of the Company, the lien of the Indenture
or the filing or the recordation  thereof, the lien of the PSCO 1939 Mortgage or
the filing or the recordation thereof, or of the validity and sufficiency of the
franchises, licenses and permits of the Company in carrying on its business.



                                          Very truly yours,



                                    C-4

<PAGE>



                                                                   Appendix IV
                                                                       to
                                                                  Distribution
                                                                    Agreement



                   CONTENTS OF LETTER OF ARTHUR ANDERSEN LLP



      The letter of Arthur  Andersen LLP will confirm that they are  independent
public  accountants  within  the  meaning  of the  1933  Act  and the  1933  Act
Regulations, and will state in effect that:

     (a)  in their opinion, the consolidated financial statements and supporting
          financial  schedules  audited by them and incorporated by reference in
          the Registration  Statement comply as to form in all material respects
          with the applicable  accounting  requirements  of the 1933 Act and the
          1934 Act and the applicable respective published rules and regulations
          thereunder;

     (b)  on the basis of a limited review (but not an audit in accordance  with
          generally accepted auditing  standards) of the unaudited  consolidated
          condensed  financial  statements,  if any,  included in the  documents
          incorporated  by  reference  in  the  Prospectus  and  of  the  latest
          available interim consolidated  financial statements of the Company, a
          reading of all recent minutes of meetings of the Board of Directors of
          the Company and the  Executive  and Audit  Committees  thereof (or for
          meetings for which minutes had not yet been prepared, discussions with
          a Company officer of the actions taken thereat),  of the  shareholders
          of the Company and of the  shareholders and Boards of Directors of the
          Company's consolidated subsidiaries,  and discussions with officers of
          the Company  responsible for financial and accounting matters and such
          other  inquiries  and  procedures  as may be specified in such letter,
          nothing came to their attention which caused them to believe that:

          (i)  the unaudited  consolidated  condensed financial  statements,  if
               any,  included in the documents  incorporated by reference in the
               Prospectus do not comply as to form in all material respects with
               the applicable  accounting  requirements  of the 1934 Act and the
               related  published  1934 Act  Regulations,  or said  consolidated
               condensed  financial   statements  are  not  in  conformity  with
               generally  accepted  accounting  principles  applied  on a  basis
               substantially  consistent  with that of the audited  consolidated
               financial statements incorporated by reference therein,

          (ii) the unaudited income statement and balance sheet amounts, if any,
               included  in  the  Prospectus  were  not  determined  on a  basis
               substantially  consistent with the audited  financial  statements
               included therein, or

         (iii) (A)  there was any  change  in the  consolidated  capital  stock,
                    other  than  ongoing  sales  under the  Company's  Automatic
                    Dividend Reinvestment and Common Stock Purchase Plan, or any
                    increase  in the  long-term  debt  of the  Company  and  its
                    consolidated  subsidiaries,  or any decrease in consolidated
                    net  assets,  at a  specified  date not more than three days
                    prior  to the  date of such  letter  as  compared  with  the
                    corresponding  amounts shown in the most recent consolidated
                    balance  sheet or condensed  balance sheet  incorporated  by
                    reference in the Prospectus, or

               (B)  there was any decrease in consolidated operating revenues or
                    net  income  for the  period  from  the  date of the  latest
                    consolidated   balance  sheet  or  condensed  balance  sheet
                    incorporated  by reference in the  Prospectus to a specified
                    date not

                                    D-1

<PAGE>



                    later than  three  days prior to the date of such  letter as
                    compared to such amounts for the corresponding period during
                    the previous year,

               except in all instances for changes, increases or decreases which
               the Prospectus  discloses have occurred or may occur or which are
               disclosed in such letter;

      (c)   they have carried out certain  procedures and made certain findings,
            specified  in such  letter,  with  respect  to certain  amounts  and
            percentages   included   in  the   Prospectus   and  the   documents
            incorporated  by reference in the Prospectus and such other items as
            the Agents may reasonably request.


                                    D-2



<PAGE>



                                                                      APPENDIX V



                                          ____________________, 19__

[Agents]

Re:   Public Service Company of Colorado Secured Medium-Term Notes

Dear Sirs:

      We have  delivered  an opinion to you dated  ______________  as counsel to
Public Service Company of Colorado (the "Company"),  pursuant to Section 5(b) of
the Distribution Agreement, dated as of ____________, among the Company and you,
as Agents.  You may continue to rely upon such opinion as if it were dated as of
this date except that all  statements  and opinions  contained  therein shall be
deemed to relate to the  Registration  Statement  and  Prospectus as amended and
supplemented to this date.

      This  letter  is  delivered  to  you  pursuant  to  Section  6(b)  of  the
Distribution Agreement.

                                          Very truly yours,

                                       V-1



                                                          
                                                                 Exhibit 4(a)(3)
================================================================================





                            SUPPLEMENTAL INDENTURE


                         Dated as of November 1, 1996



                                ________________



                      PUBLIC SERVICE COMPANY OF COLORADO



                                      TO


                           FIRST TRUST OF NEW YORK,
                             NATIONAL ASSOCIATION,

                                                                    As Trustee


                               _________________


                  Creating an Issue of First Mortgage Bonds,
                              Collateral Series D


                                _______________



      (Supplemental to Indenture dated as of December 1, 1939, as amended)





<PAGE>



            SUPPLEMENTAL INDENTURE, dated as of November 1, 1996, between PUBLIC
SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws
of the State of Colorado  (the  "Company"),  party of the first part,  and FIRST
TRUST OF NEW YORK,  NATIONAL  ASSOCIATION,  a national banking  association,  as
successor  trustee (the  "Trustee") to Morgan Guaranty Trust Company of New York
(formerly Guaranty Trust Company of New York), party of the second part.

            WHEREAS,  the  Company  heretofore  executed  and  delivered  to the
Trustee its Indenture, dated as of December 1, 1939 (the "Principal Indenture"),
to secure its First Mortgage Bonds from time to time issued thereunder; and

            WHEREAS,  the Company has  heretofore  executed and delivered to the
Trustee the Supplemental Indentures referred to in Schedule A hereto for certain
purposes,  including the creation of series of bonds, the subjection to the lien
of the Principal Indenture of property acquired after the execution and delivery
thereof,  the amendment of certain provisions of the Principal Indenture and the
appointment of the successor Trustee; and

            WHEREAS,  the Principal Indenture as supplemented and amended by all
Supplemental  Indentures  heretofore  executed by the Company and the Trustee is
hereinafter  referred to as the  "Indenture,"  and, unless the context  requires
otherwise,  references herein to Articles and Sections of the Indenture shall be
to Articles and Sections of the Principal Indenture as so amended; and

            WHEREAS,  the  Company  proposes  to  create a new  series  of First
Mortgage Bonds to be designated as First  Mortgage  Bonds,  Collateral  Series D
(the "Collateral Series D Bonds"),  to be issued and delivered from time to time
to the trustee under the 1993 Mortgage (as hereinafter defined) as the basis for
the  authentication  and  delivery  under  the  1993  Mortgage  of a  series  of
securities  constituting  medium-term notes, all as hereinafter provided, and to
vary in certain respects the covenants and provisions  contained in Article V of
the Indenture,  to the extent that such  covenants and  provisions  apply to the
Collateral Series D Bonds; and

            WHEREAS,  the Company,  pursuant to the provisions of the Indenture,
has, by appropriate  corporate  action,  duly resolved and determined to execute
this Supplemental Indenture for the purpose of providing for the creation of the
Collateral Series D Bonds and of specifying the form, provisions and particulars
thereof,  as in  the  Indenture  provided  or  permitted  and of  giving  to the
Collateral Series D Bonds the protection and security of the Indenture; and

            [WHEREAS,   the  Company  has  acquired  the   additional   property
hereinafter described,  and the Company desires that such additional property so
acquired be specifically subjected to the lien of the Indenture; and]

            WHEREAS,  the  Company  represents  that all  acts  and  proceedings
required by law and by the charter and  by-laws of the  Company,  including  all
action  requisite  on the  part of its  shareholders,  directors  and  officers,
necessary to make the Collateral  Series D Bonds,  when executed by the Company,
authenticated and delivered by the Trustee and duly issued,  the valid,  binding
and legal obligations of the Company,  and to constitute the Principal Indenture
and all indentures supplemental thereto,  including this Supplemental Indenture,
valid,  binding  and  legal  instruments  for the  security  of the bonds of all
series, including the Collateral Series D Bonds, in accordance with the terms of
such bonds and such instruments,  have been done,  performed and fulfilled,  and
the execution and delivery hereof have been in all respects duly authorized;


<PAGE>




            NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

            That Public  Service  Company of Colorado,  the Company named in the
Indenture, in consideration of the premises and of One Dollar to it duly paid by
the  Trustee at or before the  ensealing  and  delivery of these  presents,  the
receipt  whereof is hereby  acknowledged,  and in pursuance of the direction and
authority of the Board of Directors  of the Company  given at a meeting  thereof
duly called and held, and in order to create the  Collateral  Series D Bonds and
to specify the form,  terms and  provisions  thereof,  [and to make definite and
certain the lien of the Indenture upon the premises hereinafter described and to
subject said premises  directly to the lien of the Indenture,] and to secure the
payment of the principal of and premium,  if any, and  interest,  if any, on all
bonds  from  time  to  time  outstanding  under  the  Indenture,  including  the
Collateral  Series D Bonds,  according to the terms of said bonds, and to secure
the performance and observance of all of the covenants and conditions  contained
in the Indenture,  has executed and delivered this  Supplemental  Indenture [and
has granted, bargained, sold, warranted,  aliened, remised, released,  conveyed,
assigned, transferred,  mortgaged, pledged, set over and confirmed, and by these
presents does grant, bargain,  sell, warrant,  alien, remise,  release,  convey,
assign, transfer, mortgage, pledge, set over and confirm unto First Trust of New
York, National  Association,  as Trustee, and its successor or successors in the
trust and its and their assigns  forever,  the property  described in Schedule B
hereto  (which  is  described  in such  manner as to fall  within  and under the
headings or parts or  classifications  set forth in the Granting  Clauses of the
Principal Indenture)];

            TO HAVE AND TO HOLD the same and all and  singular  the  properties,
rights,  privileges and franchises  described in the Principal  Indenture and in
the  several  Supplemental  Indentures  hereinabove  referred  to  [and  in this
Supplemental  Indenture]  and owned by the Company on the date of the  execution
and delivery hereof (other than property of a character  expressly excepted from
the lien of the  Indenture  as  therein  set  forth)  unto the  Trustee  and its
successor or successors and assigns forever;

            SUBJECT, HOWEVER,  to  permitted  encumbrances  as  defined  in  the
Indenture;

            IN TRUST,  NEVERTHELESS,  upon the terms and trusts set forth in the
Indenture,  for the equal and proportionate  benefit and security of all present
and future  holders of the bonds and coupons  issued and to be issued  under the
Indenture, including the Collateral Series D Bonds, without preference, priority
or distinction as to lien (except as any sinking,  amortization,  improvement or
other fund established in accordance with the provisions of the Indenture or any
indenture  supplemental  thereto may afford additional security for the bonds of
any particular series) of any of said bonds over any others thereof by reason of
series,  priority in the time of the issue or negotiation  thereof, or otherwise
howsoever, except as provided in Section 2 of Article IV of the Indenture.



                                     -2-

<PAGE>



                                  ARTICLE ONE

           CREATION AND DESCRIPTION OF THE COLLATERAL SERIES D BONDS

            SECTION  1. A new  series  of bonds to be  issued  from time to time
under and  secured by the  Indenture  is hereby  created,  the bonds of such new
series  to  be  designated  First  Mortgage  Bonds,  Collateral  Series  D.  The
Collateral  Series D Bonds shall be limited to an aggregate  principal amount of
Two Hundred  Fifty Million  dollars  ($250,000,000),  excluding  any  Collateral
Series D Bonds which may be authenticated  and exchanged for or in lieu of or in
substitution for or on transfer of other  Collateral  Series D Bonds pursuant to
any  provisions of the Indenture.  The Collateral  Series D Bonds shall not bear
interest and each Collateral Series D Bond shall (a) be issued in such principal
amount,  (b) mature on such date not less than nine  months nor more than thirty
years from its Original Issue Date (as hereinafter  defined),  and (c) have such
other terms and conditions as shall not be  inconsistent  with the provisions of
the  Indenture,  all as shall be  specified  by the  Company  in a  certificate,
executed by the President,  any Vice  President,  the Treasurer or any Assistant
Treasurer of the Company,  delivered to the Trustee  relating to such Collateral
Series  D  Bond  and  referring  to  this  Supplemental   Indenture  (each  such
certificate being deemed to constitute a part of this Supplemental Indenture and
being   hereinafter   sometimes   called  an   "Issuance   Certificate"),   such
specification  by such an officer  of the  Company  in an  Issuance  Certificate
having been  heretofore  authorized in a resolution of the Board of Directors of
the Company.

            The  principal  of each  Collateral  Series D Bond shall be payable,
upon presentation thereof, at the office or agency of the Company in the city in
which the  principal  corporate  trust office of the 1993  Mortgage  Trustee (as
hereinafter defined) is located, in any coin or currency of the United States of
America  which at the time of payment  shall be legal  tender for the payment of
public and private debts.

            The  Collateral  Series D Bonds shall be issued and  delivered  from
time to time by the Company to First Trust of New York, National Association, as
successor  trustee  under  the  Indenture,  dated  as of  October  1,  1993,  as
supplemented  (the "1993  Mortgage"),  of the Company to such trustee (the "1993
Mortgage  Trustee"),  as the basis for the authentication and delivery under the
1993 Mortgage of a series of securities.  As provided in the 1993 Mortgage,  the
Collateral  Series D Bonds will be  registered  in the name of the 1993 Mortgage
Trustee or its nominee and will be owned and held by the 1993 Mortgage  Trustee,
subject to the provisions of the 1993  Mortgage,  for the benefit of the holders
of all securities from time to time outstanding under the 1993 Mortgage, and the
Company shall have no interest therein.

            Any payment by the Company  under the 1993 Mortgage of the principal
of any securities  which shall have been  authenticated  and delivered under the
1993  Mortgage on the basis of the issuance  and  delivery to the 1993  Mortgage
Trustee of  Collateral  Series D Bonds  (other  than by the  application  of the
proceeds of a payment in respect of such  Collateral  Series D Bonds) shall,  to
the extent  thereof,  be deemed to satisfy and discharge  the  obligation of the
Company,  if any, to make a payment of  principal  of such  Collateral  Series D
Bonds which is then due.

            The Trustee may  conclusively  presume  that the  obligation  of the
Company to pay the principal of any Collateral  Series D Bonds as the same shall
become due and payable shall

                                     -3-

<PAGE>



have been fully satisfied and discharged unless and until it shall have received
a written notice from the 1993 Mortgage Trustee, signed by an authorized officer
thereof,  stating that the principal of specified  Collateral Series D Bonds has
become due and payable and has not been fully paid, and specifying the amount of
funds required to make such payment.

            Each  Collateral  Series D Bond shall be dated as of the date of its
authentication.

            The  Collateral  Series D Bonds shall be issued as fully  registered
bonds only, in denominations of $1,000 and integral multiples thereof.

            The Collateral Series D Bonds shall be registerable and exchangeable
at the  office  or  agency of the  Company  in the city in which  the  principal
corporate  trust office of the 1993 Mortgage  Trustee is located,  in the manner
and upon the terms  set  forth in  Section  5 of  Article  II of the  Indenture;
provided, however, that the Collateral Series D Bonds shall not be transferrable
except to a successor  trustee under the 1993 Mortgage.  No service charge shall
be made for any exchange or transfer of any Collateral Series D Bond.

            If  and  to  the  extent   necessary  to   eliminate   any  apparent
inconsistency  between any  provision  of this  Supplemental  Indenture  and any
provision  of the  Indenture  all  Collateral  Series  D Bonds  having  the same
Original  Issue  Date,  Stated  Maturity,  interest  rate,  and other  terms and
conditions  shall be deemed to be a separate series of bonds,  and such Original
Issue  Date,  Stated  Maturity,  interest  rate,  if any,  and  other  terms and
conditions shall be deemed to be a part of the designation of such series.

            As used  herein,  the term  "Original  Issue Date" shall mean,  with
respect to any Collateral Series D Bond, the date of authentication and delivery
hereunder of such  Collateral  Series D Bond,  or, in the case of any particular
Collateral  Series D Bond which has been  authenticated  and delivered  upon the
registration  of  transfer  or  exchange  of, or in  substitution  for,  another
Collateral Series D Bond, the date of the original  authentication  and delivery
hereunder of the first  Collateral  Series D Bond  authenticated  and  delivered
hereunder representing all or a portion of the same obligation as that evidenced
by such particular  Collateral  Series D Bond; the term "Stated  Maturity" shall
mean,  with  respect  to any  Collateral  Series D Bond,  the date on which  the
principal  of such  Collateral  Series D Bond is  stated  to be due and  payable
(without  regard  to any  provision  for  acceleration,  redemption  or  similar
provisions);  and the term "Maturity" shall mean, with respect to any Collateral
Series D Bond, the date on which the principal of such Collateral  Series D Bond
becomes  due  and  payable,  whether  at  Stated  Maturity,  by  declaration  of
acceleration, upon call for redemption or otherwise.

            SECTION  2.  The  text of the  Collateral  Series  D Bonds  shall be
substantially in the form attached hereto as Exhibit A.

            SECTION  3. The  Collateral  Series D Bonds may be  executed  by the
Company and delivered to the Trustee and, upon  compliance  with all  applicable
provisions  and  requirements  of the  Indenture  in respect  thereof,  shall be
authenticated  by the  Trustee and  delivered  (without  awaiting  the filing or
recording of this Supplemental Indenture), from time to time, in accordance with
the written order or orders of the Company.



                                     -4-

<PAGE>



                                  ARTICLE TWO

                  REDEMPTION OF THE COLLATERAL SERIES D BONDS

            SECTION 1. Each Collateral  Series D Bond shall be redeemable at the
option of the Company in whole at any time, or in part from time to time,  prior
to Stated Maturity,  at a redemption price equal to 100% of the principal amount
thereof to be redeemed.

            SECTION 2. The  provisions of Sections 3, 4, 5, 6 and 7 of Article V
of the Indenture  shall be applicable to the Collateral  Series D Bonds,  except
that (a) no publication of notice of redemption of the Collateral Series D Bonds
shall be required and (b) if less than all the Collateral  Series D Bonds are to
be redeemed, the Collateral Series D Bonds to be redeemed shall be selected from
the maturities,  and in the principal amounts,  designated to the Trustee by the
Company,  and except as such provisions may otherwise be  inconsistent  with the
provisions of this Article Two.

            SECTION  3. The  holder of each and every  Collateral  Series D Bond
issued  hereunder  hereby  agrees  to  accept  payment  thereof  prior to Stated
Maturity on the terms and conditions provided for in this Article Two.


                                ARTICLE THREE.

                        ACKNOWLEDGMENT OF RIGHT TO VOTE
                          OR CONSENT WITH RESPECT TO
                       CERTAIN AMENDMENTS TO INDENTURE

            The  Company  hereby  acknowledges  the right of the  holders of the
Collateral  Series D Bonds to vote or consent  with respect to any or all of the
modifications to the Indenture  referred to in Article Three of the Supplemental
Indenture, dated as of March 1, 1980, irrespective of the fact that the Bonds of
the Second 1987 Series are no longer outstanding;  provided,  however, that such
acknowledgment  shall  not  impair  (a) the  right of the  Company  to make such
modifications without the consent or other action of the holders of the Bonds of
the 2020 Series or the bonds of any other series subsequently  created under the
Indenture with respect to which the Company has expressly reserved such right or
(b) the right of the  Company  to reserve  the right to make such  modifications
without the consent or other  action of the holders of bonds of one or more,  or
any or all, series created subsequent to the creation of the Collateral Series D
Bonds.


                                 ARTICLE FOUR

                                  THE TRUSTEE

            The  Trustee  accepts  the  trusts  created  by  this   Supplemental
Indenture  upon the terms and  conditions  set forth in the  Indenture  and this
Supplemental Indenture.  The recitals in this Supplemental Indenture are made by
the  Company  only and not by the  Trustee.  Each and every  term and  condition
contained in Article XII of the Indenture shall apply to this

                                     -5-

<PAGE>



Supplemental Indenture with the same force and effect as if the same were herein
set forth in full, with such omissions,  variations and modifications thereof as
may be appropriate to make the same conform to this Supplemental Indenture.


                                 ARTICLE FIVE

                           MISCELLANEOUS PROVISIONS


            SECTION 1.  Subject to the  variations  contained  in Article Two of
this  Supplemental  Indenture,  the  Indenture is in all  respects  ratified and
confirmed and the Principal Indenture, this Supplemental Indenture and all other
indentures  supplemental  to the Principal  Indenture  shall be read,  taken and
construed  as one  and  the  same  instrument.  Neither  the  execution  of this
Supplemental  Indenture  nor  anything  herein  contained  shall be construed to
impair the lien of the Indenture on any of the properties  subject thereto,  and
such lien shall  remain in full force and effect as  security  for all bonds now
outstanding or hereafter issued under the Indenture.

            All covenants and provisions of the Indenture shall continue in full
force  and  effect  and  this  Supplemental  Indenture  shall  form  part of the
Indenture.

            SECTION 2. If the date for  making any  payment or the last date for
performance  of any act or the  exercising  of any right,  as  provided  in this
Supplemental  Indenture,  shall not be a  Business  Day (as  defined in the 1993
Mortgage),  such payment may be made or act performed or right  exercised on the
next  succeeding  Business  Day with the same force and effect as if done on the
nominal date provided in this Supplemental Indenture.

            SECTION  3.  The  terms  defined  in the  Indenture  shall,  for all
purposes  of this  Supplemental  Indenture,  have the meaning  specified  in the
Indenture  except as set forth in  Section 4 of this  Article or  otherwise  set
forth in this  Supplemental  Indenture or unless the context  clearly  indicates
some other meaning to be intended.

            SECTION 4. Any term  defined in Section  303 of the Trust  Indenture
Act of 1939, as amended,  and not otherwise defined in the Indenture shall, with
respect to this  Supplemental  Indenture and the Collateral Series D Bonds, have
the meaning  assigned to such term in Section 303 as in force on the date of the
execution of this Supplemental Indenture.

            SECTION 5. This Supplemental Indenture may be executed in any number
of counterparts, and all of said counterparts executed and delivered, each as an
original, shall constitute but one and the same instrument.

            IN WITNESS WHEREOF, Public Service Company of Colorado, party hereto
of the first part,  has caused its corporate  name to be hereunto  affixed,  and
this  instrument  to be signed by its President or any Vice  President,  and its
corporate  seal to be hereunto  affixed  and  attested  by its  Secretary  or an
Assistant Secretary for and in its behalf; and First Trust of New York, National
Association,  the party hereto of the second part, in evidence of its acceptance
of the trust  hereby  created,  has caused  its  corporate  name to be  hereunto
affixed, and this instrument to

                                     -6-

<PAGE>



be signed and its corporate seal to be affixed by one of its Vice Presidents and
attested by one of its Assistant  Secretaries,  for and in its behalf, all as of
the day and year first above written.

                                          PUBLIC SERVICE COMPANY OF COLORADO



                                          By:________________________________
                                               [Name]
                                               [Title]

ATTEST:___________________________
         [Name]
         [Assistant Secretary]

                                          FIRST TRUST OF NEW YORK,
                                          NATIONAL ASSOCIATION,
                                                as Trustee


                                          By:________________________________
                                               [Name]
                                               Vice President


ATTEST:________________________
         [Name]
         Assistant Secretary


                                     -7-

<PAGE>



STATE OF COLORADO         )
                          )  ss.:
CITY AND COUNTY OF DENVER )


        On  this  _____  day  of  ______,  before  me,  ______________,  a  duly
authorized Notary Public in and for said City and County in the State aforesaid,
personally  appeared  __________  and  _______________,  to  me  known  to  be a
_________________________  and a  __________________,  respectively,  of  PUBLIC
SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws
of the State of Colorado,  one of the corporations  that executed the within and
foregoing  instrument;  and the said  __________ and  _____________,  severally,
acknowledged  the said  instrument  to be the free and voluntary act and deed of
said  corporation,  for the uses and  purposes  therein  mentioned,  and on oath
stated that they were  authorized to execute said  instrument  and that the seal
affixed thereto is the corporate seal of said corporation.

        IN WITNESS WHEREOF,  I have hereunto set my hand and affixed my official
seal the day and year first above written.



                                        __________________________________
                                        Notary Public


                                     -8-

<PAGE>




STATE OF NEW YORK                )
                                 )  ss.:
CITY AND COUNTY OF NEW YORK      )


        On  this  ____  day  of  ____,  before  me,  _________________,  a  duly
authorized Notary Public in and for said City and County in the State aforesaid,
personally  appeared  ______________  and  _____________,  to me  known  to be a
_________________ and an __________________, respectively, of First TRUST OF NEW
YORK,  National  Association,  a  national  banking  association,   one  of  the
corporations  that  executed the within and foregoing  instrument;  and the said
________________ and ______________, severally, acknowledged the said instrument
to be the free and voluntary act and deed of said corporation,  for the uses and
purposes  therein  mentioned,  and on oath stated that they were  authorized  to
execute said  instrument and that the seal affixed thereto is the corporate seal
of said corporation.

        IN WITNESS WHEREOF,  I have hereunto set my hand and affixed my official
seal the day and year first above written.


                                   ______________________________________
                                   Notary Public
                                   

                                     -9-

<PAGE>



                                                                     EXHIBIT A



                       FORM OF COLLATERAL SERIES D BOND

        This bond is not  transferable  except to a successor  trustee under the
Indenture, dated as of October 1, 1993, as supplemented,  between Public Service
Company  of  Colorado  and First  Trust of New York,  National  Association,  as
successor trustee thereunder.


                      PUBLIC SERVICE COMPANY OF COLORADO

                             FIRST MORTGAGE BOND,

                              CoLLATERAL SERIES D



REGISTERED                                                 REGISTERED


No..................                                       $..................

                      Original Issue Date:
                      Stated Maturity:


        FOR VALUE RECEIVED,  PUBLIC SERVICE  COMPANY OF COLORADO,  a corporation
organized  and  existing  under the laws of the State of  Colorado  (hereinafter
sometimes  called the  "Company"),  promises  to pay to First Trust of New York,
National  Association,  as successor trustee (the "1993 Mortgage Trustee") under
the  Indenture,  dated as of  October  1, 1993  (the  "1993  Mortgage"),  of the
Company, or registered assigns,


Dollars on the Stated  Maturity  specified above (unless this bond shall then be
deemed to have been paid in  accordance  with the  provisions  of the  Indenture
referred  to below) at the office or agency of the  Company in the city in which
the principal  corporate  trust office of the 1993 Mortgage  Trustee is located.
This bond shall not bear  interest.  The principal of this bond shall be payable
in any coin or  currency  of the United  States of America  which at the time of
payment shall be legal tender for the payment of public and private debts.

        Any payment by the Company  under the 1993  Mortgage of the principal of
securities  which shall have been  authenticated  and  delivered  under the 1993
Mortgage on the basis of the issuance and delivery to the 1993 Mortgage  Trustee
of this bond (the "1993 Mortgage  Securities") (other than by the application of
the proceeds of a payment in respect of this bond) shall, to the extent thereof,
be deemed to satisfy and  discharge the  obligation  of the Company,  if any, to
make a payment of principal of this bond which is then due.

                                     A-1

<PAGE>




        This bond is one of an issue of bonds of the  Company,  issued and to be
issued in one or more series  under and equally and ratably  secured  (except as
any sinking, amortization,  improvement or other fund, established in accordance
with  the  provisions  of  the  indenture  hereinafter  mentioned,   may  afford
additional  security  for the  bonds  of any  particular  series)  by a  certain
indenture,  dated as of December 1, 1939,  made by the Company to First Trust of
New York,  National  Association as successor  trustee  (hereinafter  called the
"Trustee"),  to Morgan  Guaranty  Trust Company of New York  (formerly  Guaranty
Trust Company of New York), as amended and  supplemented  by several  indentures
supplemental thereto,  including the Supplemental Indenture dated as of November
1,  1996  (said  Indenture  as  amended  and  supplemented  by  said  indentures
supplemental  thereto  being  hereinafter  called  the  "Indenture"),  to  which
Indenture  reference is hereby made for a description of the property mortgaged,
the nature and extent of the security,  the rights and  limitations of rights of
the Company,  the Trustee,  and the holders of said bonds,  under the Indenture,
and the terms and  conditions  upon which said bonds are secured,  to all of the
provisions of which  Indenture  and of all  indentures  supplemental  thereto in
respect of such security,  including the provisions of the Indenture  permitting
the issue of bonds of any series for property which,  under the restrictions and
limitations therein specified,  may be subject to liens prior to the lien of the
Indenture,  the holder, by accepting this bond, assents. To the extent permitted
by and as provided in the Indenture,  the rights and  obligations of the Company
and of the holders of said bonds  (including  those pertaining to any sinking or
other fund) may be changed and modified, with the consent of the Company, by the
holders  of at  least  75% in  aggregate  principal  amount  of the  bonds  then
outstanding (excluding bonds disqualified from voting by reason of the Company's
interest therein as provided in the Indenture);  provided, however, that without
the consent of the holder hereof no such  modification  or  alteration  shall be
made which will  extend  the time of  payment of the  principal  of this bond or
reduce the principal amount hereof or effect any other modification of the terms
of payment of such principal or will reduce the percentage of bonds required for
the aforesaid actions under the Indenture. The Company has reserved the right to
amend the Indenture without any consent or other action by holders of any series
of bonds created after October 31, 1975  (including this series) so as to change
75% in the foregoing sentence to 60% and to change certain  procedures  relating
to bondholders'  meetings.  This bond is one of a series of bonds  designated as
the First Mortgage Bonds, Collateral Series D, of the Company.

        This bond shall be  redeemable  at the option of the Company in whole at
any time, or in part from time to time,  prior to the Stated Maturity  specified
above, at a redemption price equal to 100% of the principal amount thereof to be
redeemed.

        The  principal of this bond may be declared or may become due before the
Stated Maturity  specified  above,  on the conditions,  in the manner and at the
times set forth in the  Indenture,  upon the happening of an event of default as
therein provided.

        This bond is not  transferable  except to a successor  trustee under the
1993  Mortgage,  any such  transfer  to be made at the  office  or agency of the
Company in the city in which the  principal  corporate  trust office of the 1993
Mortgage  Trustee is located,  upon surrender and cancellation of this bond, and
thereupon  a new bond of this series of a like  principal  amount and having the
same Original Issue Date,  Stated Maturity and other terms and conditions,  will
be issued to the transferee in exchange therefor,  as provided in the Indenture.
The Company,  the Trustee, any paying agent and any registrar may deem and treat
the person in whose name this bond is  registered  as the absolute  owner hereof
for the purpose of receiving payment and for all other

                                     A-2

<PAGE>



purposes.  This bond,  alone or with  other  bonds of this  series,  may in like
manner be  exchanged  at such office or agency for one or more new bonds of this
series of the same  aggregate  principal  amount,  and having the same  Original
Issue Date, Stated Maturity, and other terms and conditions,  all as provided in
the Indenture. No service charge shall be made to any holder of any bond of this
series for any exchange or transfer of bonds.

        No recourse  under or upon any covenant or obligation of the  Indenture,
or of any bonds thereby secured, or for any claim based thereon, or otherwise in
any manner in respect thereof, shall be had against any incorporator, subscriber
to the capital stock, shareholder, officer or director, as such, of the Company,
whether former,  present or future,  either directly,  or indirectly through the
Company or the Trustee, by the enforcement of any subscription to capital stock,
assessment  or otherwise,  or by any legal or equitable  proceeding by virtue of
any statute or otherwise  (including,  without  limiting the  generality  of the
foregoing,  any proceeding to enforce any claimed  liability of  shareholders of
the Company based upon any theory of  disregarding  the corporate  entity of the
Company  or upon  any  theory  that  the  Company  was  acting  as the  agent or
instrumentality   of  the   shareholders),   any  and  all  such   liability  of
incorporators, shareholders, subscribers, officers and directors, as such, being
released  by the  holder  hereof,  by the  acceptance  of this  bond,  and being
likewise waived and released by the terms of the Indenture under which this bond
is issued.

        This bond shall not be valid or become  obligatory for any purpose until
the  certificate  of  authentication  endorsed  hereon shall have been signed by
First Trust of New York,  National  Association,  or its  successor,  as Trustee
under the Indenture.



                                     A-3

<PAGE>




        IN WITNESS  WHEREOF,  Public Service Company of Colorado has caused this
bond to be  signed  in its name by the  facsimile  signature  of a  Senior  Vice
President  and its  corporate  seal to be  imprinted  hereon and attested by the
facsimile signature of its Secretary.

Dated:                                  PUBLIC SERVICE COMPANY OF COLORADO



                                        By:_______________________________
                                               Senior Vice President

ATTEST:________________________
              Secretary





                         CERTIFICATE OF AUTHENTICATION


        This is one of the securities of the Series designated  therein referred
to in the within-mentioned Supplemental Indenture.

Dated:                                  FIRST TRUST OF NEW YORK,
                                        NATIONAL ASSOCIATION,
                                          AS TRUSTEE


                                        By:_______________________________
                                                 Authorized Officer

                                     A-4

<PAGE>



                                                                    SCHEDULE A
<TABLE>
<CAPTION>


                            SUPPLEMENTAL INDENTURES


     Date of                                                          Principal
  Supplemental                                      Principal           Amount
    Indenture            Series of Bonds          Amount Issued      Outstanding
    ---------            ---------------          -------------      -----------
<S>                  <C>                           <C>                  <C>

March 14, 1941                 None                     --                --

May 14, 1941                   None                     --                --

April 28, 1942                 None                     --                --

April 14, 1943                 None                     --                --

April 27, 1944                 None                     --                --

April 18, 1945                 None                     --                --

April 23, 1946                 None                     --                --

April 9, 1947                  None                     --                --

June 1, 1947*         2-7/8% Series due 1977       $ 40,000,000          None

April 1, 1948                  None                     --                --

May 20, 1948                   None                     --                --

October 1, 1948       3-1/8% Series due 1978        10,000,000           None

April 20, 1949                 None                     --                --

April 24, 1950                 None                     --                --

April 18, 1951                 None                     --                --

October 1, 1951       3-1/4% Series due 1981        15,000,000           None

April 21, 1952                 None                     --                --

December 1, 1952               None                     --                --

April 15, 1953                 None                     --                --

April 19, 1954                 None                     --                --

October 1, 1954*      3-1/8% Series due 1984        20,000,000           None

April 18, 1955                 None                     --                --

April 24, 1956                 None                     --                --

May 1, 1957*          4-3/8% Series due 1987        30,000,000           None

April 10, 1958                 None                     --                --

May 1, 1959           4-5/8% Series due 1989        20,000,000           None

April 18, 1960                 None                     --                --
</TABLE>


                                       I-1

<PAGE>
<TABLE>
<CAPTION>



     Date of                                                          Principal
  Supplemental                                      Principal           Amount
    Indenture            Series of Bonds          Amount Issued      Outstanding
    ---------            ---------------          -------------      -----------
<S>                   <C>                           <C>               <C> 

April 19, 1961                 None                     --                --

October 1, 1961       4-1/2% Series due 1991        30,000,000           None

March 1, 1962         4-5/8% Series due 1992         8,800,000           None

June 1, 1964          4-1/2% Series due 1994        35,000,000           None

May 1, 1966           5-3/8% Series due 1996        35,000,000           None

July 1, 1967*         5-7/8% Series due 1997        35,000,000       35,000,000

July 1, 1968*         6-3/4% Series due 1998        25,000,000       25,000,000

April 25, 1969                 None                     --                --

April 21, 1970                 None                     --                --

September 1, 1970     8-3/4% Series due 2000        35,000,000           None

February 1, 1971      7-1/4% Series due 2001        40,000,000           None

August 1, 1972        7-1/2% Series due 2002        50,000,000           None

June 1, 1973          7-5/8% Series due 2003        50,000,000           None

March 1, 1974       Pollution Control Series A      24,000,000       22,500,000

December 1, 1974    Pollution Control Series B      50,000,000           None

October 1, 1975       9-3/8% Series due 2005        50,000,000           None

April 28, 1976                 None                     --                --

April 28, 1977                 None                     --                --

November 1, 1977*     8-1/4% Series due 2007        50,000,000           None

April 28, 1978                 None                     --                --

October 1, 1978       9-1/4% Series due 2008        50,000,000           None

October 1, 1979*    Pollution Control Series C      50,000,000           None

March 1, 1980*         15% Series due 1987          50,000,000           None

April 28, 1981                 None                     --                --

November 1, 1981*   Pollution Control Series D      27,380,000           None

December 1, 1981*    16-1/4% Series due 2011        50,000,000           None

April 29, 1982                 None                     --                --

May 1, 1983*        Pollution Control Series E      42,000,000           None

April 30, 1984                 None                     --                --

March 1, 1985*         13% Series due 2015          50,000,000           None
</TABLE>


                                       I-2

<PAGE>
<TABLE>
<CAPTION>



     Date of                                                          Principal
  Supplemental                                      Principal           Amount
    Indenture            Series of Bonds          Amount Issued      Outstanding
    ---------            ---------------          -------------      -----------
<S>                 <C>                            <C>              <C> 
November 1, 1986*   Pollution Control Series F      27,250,000       27,250,000

May 1, 1987*          8.95% Series due 1992         75,000,000           None

July 1, 1990*         9-7/8% Series due 2020        75,000,000       75,000,000

December 1, 1990*   Secured Medium-Term Notes,     191,500,000**    108,500,000*
                             Series A

March 1, 1992*      8-1/8% Series due 2004 and      100,000,000     100,000,000
                      8-3/4% Series due 2022        150,000,000     150,000,000

April 1, 1993*      Pollution Control Series G      79,500,000       79,500,000

June 1, 1993*       Pollution Control Series H      50,000,000       50,000,000

November 1, 1993*      Collateral Series A         134,500,000      134,500,000



January 1, 1994*   Collateral Series B due 2001    102,667,000      102,667,000
                   Collateral Series B due 2024    110,000,000      110,000,000

September 2, 1994        (appointment of               None              None
                        successor trustee)

May 1, 1996*           Collateral Series C          125,000,000     125,000,000
                             due 2006
</TABLE>






* Contains amendatory provisions
** $200,000,000 authorized





                                     I-3

<PAGE>





                                                      SCHEDULE B

                             PROPERTY DESCRIPTION






                                     II-1


                                                            Exhibit 4(b)(3)


               __________________________________________________




                            PUBLIC SERVICE COMPANY
                                  OF COLORADO


                                      TO


                           FIRST TRUST OF NEW YORK,
                             NATIONAL ASSOCIATION,

                                                       as Trustee


                                _________________



                         Supplemental Indenture No. 5

                         Dated as of November 1, 1996


                         Supplemental to the Indenture
                          dated as of October 1, 1993


                                ________________


                  Establishing the Securities of Series No. 4
                designated Secured Medium-Term Notes, Series B


               __________________________________________________

         


<PAGE>



      SUPPLEMENTAL INDENTURE NO. 5, dated as of November 1, 1996, between PUBLIC
SERVICE COMPANY OF COLORADO, a corporation duly organized and existing under the
laws of the State of Colorado (hereinafter sometimes called the "Company"),  and
FIRST TRUST OF NEW YORK,  NATIONAL  ASSOCIATION,  a national banking association
(hereinafter  sometimes  called the "Trustee"),  as successor  trustee to Morgan
Guaranty Trust Company of New York under the  Indenture,  dated as of October 1,
1993 (hereinafter called the "Original Indenture"),  as previously  supplemented
and as further  supplemented by this Supplemental  Indenture No. 5. The Original
Indenture and any and all indentures and other instruments  supplemental thereto
are hereinafter sometimes collectively called the "Indenture".

                            Recitals of the Company

      The Original  Indenture  was  authorized,  executed  and  delivered by the
Company to provide for the issuance  from time to time of its  Securities  (such
term and all other capitalized  terms used herein without  definition having the
meanings  assigned to them in the  Original  Indenture),  to be issued in one or
more series as contemplated  therein, and to provide security for the payment of
the principal of and premium, if any, and interest, if any, on the Securities.

      The Company  has  heretofore  executed  and  delivered  to the Trustee the
Supplemental  Indentures  referred  to in  Schedule A hereto for the  purpose of
establishing various series of bonds and of appointing the successor trustee.

      The Company  desires to establish a series of  Securities to be designated
"Secured Medium- Term Notes, Series B", being a series of First Collateral Trust
Bonds, such series of Securities to be hereinafter  sometimes called "Series No.
4".

     The  Company  has  duly  authorized  the  execution  and  delivery  of this
Supplemental Indenture No. 5 to establish the Securities of Series No. 4 and has
duly authorized the issuance of such Securities;  and all acts necessary to make
this Supplemental  Indenture No. 5 a valid agreement of the Company, and to make
the  Securities  of Series No. 4 valid  obligations  of the  Company,  have been
performed.

                               Granting Clauses

     NOW,  THEREFORE,  THIS  SUPPLEMENTAL  INDENTURE NO. 5 WITNESSETH,  that, in
consideration  of the  premises  and of the  purchase of the  Securities  by the
Holders  thereof,  and in order to secure the  payment of the  principal  of and
premium,  if any,  and  interest,  if any, on all  Securities  from time to time
Outstanding  and the performance of the covenants  contained  therein and in the
Indenture and to declare the terms and  conditions on which such  Securities are
secured, the Company hereby grants, bargains, sells, releases, conveys, assigns,
transfers, mortgages, pledges, sets over and confirms to the Trustee, and grants
to the Trustee a security interest in, the following:

                             Granting Clause First

            All right, title and interest of the Company,  as of the date of the
      execution  and delivery of this  Supplemental  Indenture  No. 5, in and to
      property  (other than  Excepted  Property),  real,  personal and mixed and
      wherever situated, in any case used or to be used in or in connection with
      the Electric Utility Business  (whether or not such use is the sole use of
      such property),  including without limitation [(a) all lands and interests
      in land  described  or referred  to in  Schedule B hereto];  (b) all other
      lands, easements,  servitudes,  licenses, permits, rights of way and other
      rights and interests in or relating to real property used or to be used in
      or in connection with the


<PAGE>



      Electric Utility Business or relating to the occupancy or use of such real
      property,  subject however,  to the exceptions and exclusions set forth in
      clause (a) of Granting  Clause  First of the Original  Indenture;  (c) all
      plants,  generators,   turbines,   engines,  boilers,  fuel  handling  and
      transportation  facilities, air and water pollution control and sewage and
      solid waste disposal facilities and other machinery and facilities for the
      generation  of  electric  energy;  (d)  all  switchyards,  lines,  towers,
      substations,  transformers  and other  machinery  and  facilities  for the
      transmission  of  electric  energy;  (e)  all  lines,   poles,   conduits,
      conductors,  meters, regulators and other machinery and facilities for the
      distribution of electric energy;  (f) all buildings,  offices,  warehouses
      and  other  structures  used or to be used in or in  connection  with  the
      Electric  Utility  Business;  (g) all pipes,  cables,  insulators,  ducts,
      tools,  computers and other data processing  and/or storage  equipment and
      other  equipment,  apparatus  and  facilities  used or to be used in or in
      connection  with  the  Electric  Utility  Business;  (h) any or all of the
      foregoing  properties  in the process of  construction;  and (i) all other
      property,  of whatever kind and nature,  ancillary to or otherwise used or
      to be used in  conjunction  with any or all of the foregoing or otherwise,
      directly or indirectly, in furtherance of the Electric Utility Business;

                            Granting Clause Second

            Subject to the applicable  exceptions  permitted by Section  810(c),
      Section  1303 and Section  1305 of the  Original  Indenture,  all property
      (other  than  Excepted  Property)  of the kind  and  nature  described  in
      Granting Clause First which may be hereafter  acquired by the Company,  it
      being the intention of the Company that all such property  acquired by the
      Company after the date of the execution and delivery of this  Supplemental
      Indenture  No. 5 shall be as fully  embraced  within and  subjected to the
      Lien hereof as if such  property  were owned by the Company as of the date
      of the execution and delivery of this Supplemental Indenture No. 5;

                            Granting Clause Fourth

            All other property of whatever kind and nature subjected or required
      to be  subjected  to the Lien of the  Indenture  by any of the  provisions
      thereof;

                               Excepted Property

            Expressly  excepting  and  excluding,  however,  from  the  Lien and
      operation of the Indenture all Excepted  Property of the Company,  whether
      now owned or hereafter acquired;

      TO HAVE AND TO HOLD all such property,  real, personal and mixed, unto the
Trustee, its successors in trust and their assigns forever;

      SUBJECT,  HOWEVER,  to (a) Liens existing at the date of the execution and
delivery of the Original Indenture  (including,  but not limited to, the Lien of
the PSCO 1939  Mortgage),  (b) as to property  acquired by the Company after the
date of the execution and delivery of the Original Indenture,  Liens existing or
placed  thereon  at the  time of the  acquisition  thereof  (including,  but not
limited to, the Lien of any Class A Mortgage  and  purchase  money  Liens),  (c)
Retained  Interests and (d) any other Permitted Liens, it being understood that,
with respect to any property  which was at the date of execution and delivery of
the Original Indenture or thereafter became or hereafter becomes

                                     2

<PAGE>



subject to the Lien of any Class A Mortgage,  the Lien of the Indenture shall at
all  times be  junior,  subject  and  subordinate  to the  Lien of such  Class A
Mortgage;

      IN  TRUST,  NEVERTHELESS,  for the  equal and  proportionate  benefit  and
security of the Holders from time to time of all Outstanding  Securities without
any priority of any such Security over any other such Security;

      PROVIDED,  HOWEVER,  that the right,  title and interest of the Trustee in
and to the  Mortgaged  Property  shall  cease,  terminate  and  become  void  in
accordance with, and subject to the conditions set forth in, Article Nine of the
Original  Indenture,  and if, thereafter,  the principal of and premium, if any,
and  interest,  if any,  on the  Securities  shall have been paid to the Holders
thereof,  or shall have been paid to the Company  pursuant to Section 603 of the
Original Indenture, then and in that case the Indenture shall terminate, and the
Trustee shall execute and deliver to the Company such instruments as the Company
shall require to evidence such  termination;  otherwise the  Indenture,  and the
estate and rights thereby granted, shall be and remain in full force and effect;
and

      THE PARTIES HEREBY FURTHER COVENANT AND AGREE as follows:

                                  ARTICLE ONE

                          Securities of Series No. 4

      There are hereby  established  the Securities of Series No. 4, which shall
have the terms and  characteristics  set forth below (the lettered  subdivisions
set forth below corresponding to the lettered subdivisions of Section 301 of the
Original Indenture):

     (a)  the  title  of  the  Securities  of  such  series  shall  be  "Secured
     Medium-Term  Notes,  Series B",  being a series of First  Collateral  Trust
     Bonds;  provided,  however,  that, at any time after the PSCO 1939 Mortgage
     shall have been satisfied and discharged, the Company shall have the right,
     without any consent or other action by the Holders of such  Securities,  to
     change  such title in such  manner as shall be deemed by the  Company to be
     appropriate to reflect such  satisfaction and discharge,  such change to be
     evidenced in an Officer's Certificate;

     (b) there  shall be no limit  upon the  aggregate  principal  amount of the
     Securities of Series No. 4 which may be  authenticated  and delivered under
     the  Indenture.   The  Securities  of  Series  No.  4  shall  be  initially
     authenticated  and delivered  from time to time in the aggregate  principal
     amount of up to $250,000,000;

     (c)  interest  on the  Securities  of Series  No. 4 shall be payable to the
     Persons  in whose  names such  Securities  are  registered  at the close of
     business on the Regular Record Date for such interest,  except as otherwise
     expressly  provided  in the form of such  Security  attached  as  Exhibit A
     hereto;

     (d) the principal of each Security of Series No. 4 shall be payable on such
     date  as is  specified  in the  Officer's  Certificate  applicable  to such
     Security;

     (e) an Officer's  Certificate with respect to each Security of Series No. 4
     shall  specify  the rate at which such  Security of Series No. 4 shall bear
     interest,  the date from which interest shall accrue,  the Interest Payment
     Dates if other than February 1

                                     3

<PAGE>



     and August 1 of each year and the Regular  Record Dates with respect to the
     Interest Payment Dates if other than January 15 and July 15;

     (f) the  Corporate  Trust  Office  of  First  Trust of New  York,  National
     Association,  in New  York,  New York  shall be the  place at which (i) the
     principal of, premium,  if any, and interest,  if any, on the Securities of
     Series  No. 4 shall be  payable,  (ii)  registration  of  transfer  of such
     Securities  may be  effected,  (iii)  exchanges of such  Securities  may be
     effected  and (iv) notices and demands to or upon the Company in respect of
     such  Securities  and the Indenture  may be served;  and First Trust of New
     York,  National  Association,  shall  be the  Security  Registrar  for  the
     Securities;  provided,  however,  that the  Company  reserves  the right to
     change,  by one or more  Officer's  Certificates,  any  such  place  or the
     Security Registrar;  and provided,  further,  that the Company reserves the
     right to designate,  by one or more Officer's  Certificates,  its principal
     office in  Denver,  Colorado  as any such  place or itself as the  Security
     Registrar;

     (g) each  Security of Series No. 4 shall be  redeemable  only if and to the
     extent specified in the Officer's  Certificate  applicable to such Security
     of Series No. 4;

     (h) not  applicable  to any  Security of Series No. 4, except to the extent
     specified in the Officer's Certificate  applicable to a particular Security
     of Series No. 4;

     (i) the  Securities of Series No. 4 shall be issuable in  denominations  of
     $100,000 and any greater amount which is an integral multiple of $1,000;

     (j) not applicable;

     (k) not applicable;

     (l) not applicable;

     (m) not applicable;

     (n) not  applicable  to any  Security of Series No. 4, except to the extent
     specified in the Officer's Certificate  applicable to a particular Security
     of Series No. 4;

     (o) not applicable;

     (p) not applicable;

     (q) each Security of Series No. 4 is to be initially registered in the name
     of  Cede  &  Co.,  as  nominee  for  The  Depository   Trust  Company  (the
     "Depositary").  The Securities of Series No. 4 shall not be transferable or
     exchangeable,  nor shall any purported  transfer be  registered,  except as
     follows:

          (i) a  Security  of Series  No. 4 may be  transferred  in  whole,  and
          appropriate  registration of transfer effected, if such transfer is by
          such  nominee  to the  Depositary,  or by the  Depositary  to  another
          nominee  thereof,  or by any  nominee of the  Depositary  to any other
          nominee  thereof,  or by the Depositary or any nominee  thereof to any
          successor securities depositary or any nominee thereof; and

                                     4

<PAGE>




          (ii) a Security  of Series  No. 4 may be  exchanged  for  certificated
          notes  registered in the respective  names of the  beneficial  holders
          thereof, and thereafter shall be transferable without restriction, if:

                  (A) The Depositary,  or any successor  securities  depositary,
                  shall have  notified  the Company  and the Trustee  that it is
                  unwilling   or  unable  to  continue  to  act  as   securities
                  depositary  with  respect to such  Security of Series No. 4 or
                  the Company becomes aware that the Depositary has ceased to be
                  a clearing agency registered under the Securities Exchange Act
                  of 1934, as amended,  and, in any such case, the Trustee shall
                  not have been notified by the Company  within ninety (90) days
                  of the  identity of a  successor  securities  depositary  with
                  respect to such Security of Series No. 4;

                  (B) The Company shall have  delivered to the Trustee a Company
                  Order to the effect  that such  Security of Series No. 4 shall
                  be so exchangeable on and after a date specified therein; or

                  (C)  (1) an  Event  of  Default  shall  have  occurred  and be
                  continuing,  (2) the Trustee  shall have given  notice of such
                  Event of  Default  pursuant  to Section  1102 of the  Original
                  Indenture  and (3)  there  shall  have been  delivered  to the
                  Company  and the  Trustee  an Opinion of Counsel to the effect
                  that the interests of the  beneficial  owners of such Security
                  of Series No. 4 in respect thereof will be materially impaired
                  unless such owners become Holders of certificated notes.

     (r) not applicable;

     (s) no service  charge  shall be made for the  registration  of transfer or
     exchange  of any  Securities  of Series No. 4 provided,  however,  that the
     Company may require  payment of a sum  sufficient to cover any tax or other
     governmental  charge  payable  in  connection  with  any such  exchange  or
     transfer;

     (t) not applicable;

     (u) (i) If the Company  shall have  caused the  Company's  indebtedness  in
     respect  of any  Security  of  Series  No.  4 to have  been  satisfied  and
     discharged  prior to the  Maturity  of such  Security  of Series  No. 4, as
     provided  in Section 901 of the  Original  Indenture,  the  Company  shall,
     promptly after the date of such  satisfaction and discharge,  give a notice
     to each  Person  who was a Holder of any such  Security  of Series No. 4 on
     such date stating (A)(1) the aggregate principal amount of such Security of
     Series No. 4 and (2) the aggregate amount of any money (other than amounts,
     if any, deposited in respect of accrued interest on such Security of Series
     No. 4) and the aggregate principal amount of, the rate or rates of interest
     on,  and the  aggregate  fair  market  value of, any  Eligible  Obligations
     deposited pursuant to Section 901 of the Original Indenture with respect to
     such  Security of Series No. 4 and (B) that the Company  will  provide (and
     the Company shall  promptly so provide) to such Person,  or any  beneficial
     owner of such  Security of Series No. 4 holding  through  such Person (upon
     written  request  to the  Company  sent  to an  address  specified  in such
     notice),  such other information as such Person or beneficial owner, as the
     case may be,  reasonably may request in order to enable it to determine the
     federal income tax

                                     5

<PAGE>



     consequences  to it resulting  from the  satisfaction  and discharge of the
     Company's  indebtedness  in  respect  of such  Security  of  Series  No. 4.
     Thereafter, the Company shall, within forty-five (45) days after the end of
     each  calendar  year,  give to each  Person  who at any  time  during  such
     calendar  year was a  Holder  of such  Security  of  Series  No. 4 a notice
     containing  (X) such  information as may be necessary to enable such Person
     to report its income,  gain or loss for federal  income tax  purposes  with
     respect to such  Security  of Series No. 4 or the assets held on deposit in
     respect  thereof  during such calendar year or the portion  thereof  during
     which  such  Person was a Holder of such  Security  of Series No. 4, as the
     case may be (such  information  to be set forth for such calendar year as a
     whole and for each  month  during  such  year) and (Y) a  statement  to the
     effect that the Company  will provide  (and the Company  shall  promptly so
     provide) to such Person, or any beneficial owner of such Security of Series
     No. 4 holding through such Person (upon written request to the Company sent
     to an address  specified in such notice),  such other  information  as such
     Person or beneficial  owner, as the case may be,  reasonably may request in
     order to enable it to determine its income, gain or loss for federal income
     tax purposes  with respect to such  Security of Series No. 4 or such assets
     for such year or portion thereof, as the case may be. The obligation of the
     Company to provide or cause to be  provided  information  for  purposes  of
     income tax  reporting by any Person as described in the first two sentences
     of this paragraph shall be deemed to have been satisfied to the extent that
     the Company has provided or caused to be provided substantially  comparable
     information  pursuant to any  requirements of the Internal  Revenue Code of
     1986, as amended from time to time (the "Code"), and United States Treasury
     regulations thereunder.

               (ii)  Notwithstanding  the provisions of subparagraph  (i) above,
               the Company shall not be required to give any notice specified in
               such  subparagraph or to otherwise furnish any of the information
               contemplated  therein if the Company shall have  delivered to the
               Trustee an  Opinion  of Counsel to the effect  that the Holder of
               such Security of Series No. 4 will not recognize income,  gain or
               loss  for  federal  income  tax  purposes  as  a  result  of  the
               satisfaction  and  discharge  of the  Company's  indebtedness  in
               respect of such  Security of Series No. 4 and such Holder will be
               subject to federal income taxation on the same amounts and in the
               same  manner  and at the same times as if such  satisfaction  and
               discharge had not occurred.

               (iii)   Anything   in   this   clause   (u)   to   the   contrary
               notwithstanding,  the  Company  shall not be required to give any
               notice specified in subparagraph (i) or to otherwise  furnish the
               information  contemplated  therein or to deliver  any  Opinion of
               Counsel  contemplated by  subparagraph  (ii) if the Company shall
               have caused the applicable  Security of Series No. 4 to be deemed
               to have been paid for purposes of the  Indenture,  as provided in
               Section  901  of the  Original  Indenture,  but  shall  not  have
               effected the  satisfaction  and discharge of its  indebtedness in
               respect  of such  Security  of  Series  No.  4  pursuant  to such
               Section.

               (v) each Security of Series No. 4 shall be  substantially  in the
               form  attached  as Exhibit A hereto  and shall have such  further
               terms as are set forth in such form.


                                     6

<PAGE>



                                  ARTICLE TWO

                           Miscellaneous Provisions

     This  Supplemental  Indenture  No.  5  is  a  supplement  to  the  Original
Indenture.   As  previously   supplemented  and  further  supplemented  by  this
Supplemental  Indenture  No.  5,  the  Original  Indenture  is in  all  respects
ratified,  approved  and  confirmed,  and the Original  Indenture,  all previous
supplements  thereto  and  this  Supplemental  Indenture  No.  5 shall  together
constitute one and the same instrument.



                                     7

<PAGE>



            IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture No. 5 to be duly executed as of the day and year first above written.

                                          PUBLIC SERVICE COMPANY OF COLORADO


                                          By:_____________________________
                                               [Name]
                                               Senior Vice President



                                          FIRST TRUST OF NEW YORK,
                                            NATIONAL ASSOCIATION, Trustee


                                          By:_____________________________
                                               [Name]
                                               Vice President




                                     8

<PAGE>



STATE OF COLORADO                   )
                                    ) ss.:
CITY AND COUNTY OF DENVER           )


            On the day of , 1996,  before me personally came , to me known, who,
being  by me duly  sworn,  did  depose  and say that he is a of  Public  Service
Company of Colorado, one of the corporations described in and which executed the
foregoing  instrument;  and that he signed his name  thereto by authority of the
Board of Directors of said corporation.



                                            ______________________________
                                            Notary Public



                                     9

<PAGE>





STATE OF NEW YORK                         )
                                          ) ss.:
CITY AND COUNTY OF NEW YORK               )


            On  the  day  of   _______,   1996,   before  me   personally   came
______________,  to me known,  who,  being by me duly sworn,  did depose and say
that she is a _______________ of First Trust of New York, National  Association,
the national banking  association  described in and which executed the foregoing
instrument;  and that she signed her name  thereto by  authority of the Board of
Directors of said national banking association.



                                              ____________________________
                                              Notary Public





                                     10

<PAGE>



                                                                     EXHIBIT A
                               FORM OF SECURITY


                  (See legend at the end of this Security for
                 restrictions on transfer and change of form)


                      PUBLIC SERVICE COMPANY OF COLORADO


                      Secured Medium-Term Note, Series B
                     (being a First Collateral Trust Bond)


Original Issue Date:             Regular Record Dates:
Interest Rate:                   Initial Redemption Date:
Default Rate:                    Initial Redemption Percentage:
Stated Maturity:                 Annual Redemption Percentage Reduction:
Interest Payment Dates:          Optional Repayment Dates:
Addendum Attached
[  ] Yes                         Other/Additional Provisions:
[  ] No








           This Note is not a Discount Security within the meaning of
                         the within-mentioned Indenture.

                    -----------------------------------------


Principal Amount                                                  Registered No.
$                                                                 CUSIP


      PUBLIC  SERVICE  COMPANY OF COLORADO,  a  corporation  duly  organized and
existing  under the laws of the State of Colorado  (herein called the "Company,"
which term includes any successor  corporation  under the Indenture  referred to
below), for value received, hereby promises to pay to

                                   , or registered assigns, the principal sum of

Dollars  on the  Stated  Maturity  specified  above (or any  Redemption  Date or
Repayment Date as defined below),  and to pay interest thereon from the Original
Issue Date  specified  above or from the most recent  Interest  Payment  Date to
which interest has been paid or duly provided for,  semi-annually  in arrears on
the Interest  Payment Dates  specified  above in each year,  commencing with the
Interest  Payment Date next  succeeding  the Original  Interest  Date  specified
above, and at Maturity, at the Interest Rate per annum

                                    A-1

<PAGE>



specified  above,  computed on the basis of a 360-day year  consisting of twelve
30-day months,  until the principal  hereof is paid or duly provided for and, to
the extent that payment of such interest  shall be legally  enforceable,  at the
Default  Rate per annum  specified  above on any overdue  payment of  principal,
premium,  if any,  and/or  interest.  The interest so payable,  and paid or duly
provided for, on any Interest Payment Date shall, as provided in such Indenture,
be paid to the  Person  in whose  name  this  Note  (or one or more  Predecessor
Securities)  is registered  at the close of business on the Regular  Record Date
specified  above  (whether or not a Business Day) next  preceding  such Interest
Payment  Date except that if the  Original  Issue Date of this Note is after the
Regular  Record  Date  specified  above and  before the  corresponding  Interest
Payment  Date,  the first  payment of interest on this Note shall be made to the
Person  in whose  name  this  Note (or one or more  Predecessor  Securities)  is
registered  at the close of business on the Regular  Record Date with respect to
the next  succeeding  Interest  Payment  Date.  Notwithstanding  the  foregoing,
interest payable at Maturity shall be paid to the Person to whom principal shall
be paid. Except as otherwise  provided in said Indenture,  any such interest not
so paid or duly provided for shall  forthwith  cease to be payable to the Holder
on such  Regular  Record Date and may either be paid to the Person in whose name
this Note (or one or more Predecessor  Securities) is registered at the close of
business on a Special Record Date for the payment of such Defaulted  Interest to
be fixed by the Trustee, notice of which shall be given to Holders of Securities
of this series not less than 15 days prior to such Special  Record Date, or paid
in such other manner as permitted by the Indenture.


      Notwithstanding  the  foregoing,  if an  Addendum  is  attached  hereto or
"Other/Additional  Provisions"  apply  to this  Note as  specified  on the  face
hereof,  this Note shall be subject to the terms set forth in such  Addendum  or
such "Other/Additional Provisions".

      Payment of the principal of and premium, if any, on this Note and interest
hereon  at  Maturity  shall be made  upon  presentation  of this  Note (and with
respect to any applicable repayment of this Note, a duly completed election form
as contemplated below) at the Corporate Trust Office of First Trust of New York,
National Association, in New York, New York or at such other office or agency as
may be designated for such purpose by the Company from time to time.  Payment of
interest on this Note (other than  interest at Maturity)  shall be made by check
mailed to the  address of the Person  entitled  thereto  as such  address  shall
appear in the Note  Register,  except that if such Person  shall be a securities
depositary,  such  payment  may be made by such other  means in lieu of check as
shall be agreed upon by the Company, the Trustee and such Person. Payment of the
principal of and premium, if any, and interest on this Note, as aforesaid, shall
be made in such coin or currency of the United  States of America as at the time
of payment shall be legal tender for the payment of public and private debts.

      This Note is one of a duly  authorized  issue of securities of the Company
(herein called the "Notes"), issued and issuable in one or more series under and
equally secured by an Indenture,  dated as of October 1, 1993 (such Indenture as
originally  executed and delivered and as  supplemented  or amended from time to
time  thereafter,  together with any constituent  instruments  establishing  the
terms of particular  Securities,  being herein called the "Indenture"),  between
the Company  and First Trust of New York,  National  Association,  as  successor
trustee (herein called the "Trustee," which term includes any further  successor
trustee under the Indenture), to which Indenture and all indentures supplemental
thereto  reference is hereby made for a description  of the property  mortgaged,
pledged  and held in  trust,  the  nature  and  extent of the  security  and the
respective rights,  limitations of rights, duties and immunities of the Company,
the Trustee and the Holders of the  Securities  thereunder  and of the terms and
conditions  upon which the  Securities  are,  and are to be,  authenticated  and
delivered and secured. The acceptance of this Note shall be deemed to constitute
the  consent  and  agreement  by the  Holder  hereof  to all  of the  terms  and
provisions of the Indenture. This Note is one of the series designated above.


                                    A-2

<PAGE>



      If any Interest  Payment Date, any Redemption  Date or the Stated Maturity
shall not be a Business Day (as hereinafter defined), payment of the amounts due
on this Note on such date may be made on the next succeeding  Business Day; and,
if such payment is made or duly  provided for on such  Business Day, no interest
shall accrue on such amounts for the period from and after such Interest Payment
Date,  Redemption Date or Stated Maturity,  as the case may be, to such Business
Day.

      Unless otherwise specified in an Addendum attached hereto, this Note shall
not be subject to any sinking fund or other  mandatory  redemption  and,  unless
otherwise  specified on the face hereof in accordance with the provisions of the
following four  paragraphs,  this Note is not subject to optional  redemption or
repayment prior to the Stated Maturity hereof.

      This Note is subject  to  redemption  at the option of the  Company at any
time on or after the Initial  Redemption  Date,  if any,  specified  on the face
hereof,  as a whole at any time or from time to time in part,  in  increments of
$1,000  (provided that any remaining  principal  amount hereof shall be at least
$100,000),  at the  Redemption  Price (as defined  below),  plus unpaid  accrued
interest  hereon to the date fixed for redemption  (each, a "Redemption  Date").
The  "Redemption  Price" shall  initially be the Initial  Redemption  Percentage
specified on the face hereof  multiplied by the unpaid  principal amount of this
Note to be redeemed.  The Initial  Redemption  Percentage  shall decline at each
anniversary of the Initial Redemption Date by the Annual Redemption  Percentage,
if any,  specified on the face hereof until the Redemption  Price is 100% of the
unpaid principal amount to be redeemed.

      Notice of  redemption  shall be given by mail to the  Holder of this Note,
not less  than 30 days  nor  more  than 60 days  prior  to the  date  fixed  for
redemption,  all as provided  in the  Indenture.  As provided in the  Indenture,
notice of  redemption at the election of the Company as aforesaid may state that
such  redemption  shall be  conditional  upon the receipt by the Paying Agent or
Agents for this  Note,  on or prior to the date  fixed for such  redemption,  of
money sufficient to pay the principal of and premium,  if any, and interest,  on
this Note; a notice of redemption so conditioned  shall be of no force or effect
if such money is not so received  and, in such event,  the Company  shall not be
required to redeem this Note.

      In the event of  redemption of this Note in part only, a new Note or Notes
of this series,  of like tenor, for the unredeemed  portion hereof and otherwise
having  the same  terms as this Note  will be  issued in the name of the  Holder
hereof upon the cancellation hereof.

      This Note will be subject to repayment by the Company at the option of the
Holder hereof on the Optional Repayment  Date(s),  if any, specified on the face
hereof, in whole or in part in increments of $1,000 (provided that any remaining
principal amount hereof shall be at least $100,000),  at a repayment price equal
to 100% of the  unpaid  principal  amount to be  repaid,  plus  unpaid  interest
accrued hereon to the date fixed for repayment  (each a "Repayment  Date").  For
this Note to be  repaid,  this Note must be  received  not more than 60 nor less
than 30 calendar days prior to the Repayment Date, together with the form hereon
entitled  "Option to Elect  Repayment"  duly  completed,  by the  Trustee at its
Corporate  Trust Office in New York,  New York or such other office or agency as
may be designated by the Company from time to time.  Exercise of such  repayment
option by the Holder  hereof will be  irrevocable.  In the event of repayment of
this  Note in part  only,  a new Note or Notes of like  tenor  for the  unrepaid
portion  hereof and otherwise  having the same terms as this Note will be issued
in the name of the Holder hereof upon the cancellation hereof.

      If an Event of Default  shall occur and be  continuing,  the  principal of
this Note may be  declared  due and  payable  in the  manner and with the effect
provided in the Indenture.


                                    A-3

<PAGE>



      The Indenture permits,  with certain  exceptions as therein provided,  the
Trustee to enter into one or more  supplemental  indentures  for the  purpose of
adding any provisions  to, or changing in any manner or  eliminating  any of the
provisions  of, the Indenture with the consent of the Holders of not less than a
majority in  aggregate  principal  amount of the  Securities  of all series then
Outstanding  under the Indenture,  considered as one class;  provided,  however,
that if there shall be Securities of more than one series  Outstanding under the
Indenture and if a proposed  supplemental  indenture  shall directly  affect the
rights of the Holders of Securities  of one or more,  but less than all, of such
series,  then  the  consent  only of the  Holders  of a  majority  in  aggregate
principal  amount  of the  Outstanding  Securities  of all  series  so  directly
affected,  considered as one class,  shall be required;  and provided,  further,
that if the  Securities  of any series  shall have been  issued in more than one
Tranche and if the proposed  supplemental  indenture  shall directly  affect the
rights of the Holders of Securities  of one or more,  but less than all, of such
Tranches,  then the  consent  only of the  Holders  of a majority  in  aggregate
principal  amount of the  Outstanding  Securities  of all  Tranches  so directly
affected,  considered as one class,  shall be required;  and provided,  further,
that the  Indenture  permits the Trustee to enter into one or more  supplemental
indentures  for  limited   purposes  without  the  consent  of  any  Holders  of
Securities.  The Indenture also contains provisions  permitting the Holders of a
majority in principal  amount of the Securities then  Outstanding,  on behalf of
the Holders of all Securities,  to waive  compliance by the Company with certain
provisions of the  Indenture  and certain past defaults  under the Indenture and
their consequences.  Any such consent or waiver by the Holder of this Note shall
be conclusive  and binding upon such Holder and upon all future  Holders of this
Note and of any Note  issued  upon the  registration  of  transfer  hereof or in
exchange therefor or in lieu hereof,  whether or not notation of such consent or
waiver is made upon this Note.

      As provided in the  Indenture and subject to certain  limitations  therein
set forth,  this Note or any  portion of the  principal  amount  hereof  will be
deemed to have been paid for all purposes of the  Indenture  and to be no longer
Outstanding  thereunder,  and, at the  election of the  Company,  the  Company's
entire  indebtedness  in respect  thereof will be satisfied and  discharged,  if
there has been irrevocably deposited with the Trustee or any Paying Agent (other
than the Company),  in trust, money in an amount which will be sufficient and/or
Eligible  Obligations,  the principal of and interest on which when due, without
regard to any  reinvestment  thereof,  will provide moneys which,  together with
moneys so deposited,  will be  sufficient,  to pay when due the principal of and
premium, if any, and interest on this Note when due.

      As provided in the  Indenture and subject to certain  limitations  therein
set forth,  the transfer of this Note is registrable  in the Security  Register,
upon surrender of this Note for  registration of transfer at the Corporate Trust
Office of First Trust of New York, National  Association,  in New York, New York
or such other office or agency as may be  designated by the Company from time to
time,  duly endorsed by, or accompanied  by a written  instrument of transfer in
form  satisfactory  to the Company and the Security  Registrar duly executed by,
the Holder hereof or his attorney duly authorized in writing,  and thereupon one
or more new  Securities of this series of authorized  denominations  and of like
tenor  and  aggregate  principal  amount,  will  be  issued  to  the  designated
transferee or transferees.

      The Notes are issuable only as registered Notes,  without coupons,  and in
denominations  of $100,000  and in any greater  amount in integral  multiples of
$1,000. As provided in the Indenture and subject to certain  limitations therein
set forth, the Notes are  exchangeable for a like aggregate  principal amount of
Notes of the same  series  and  Tranche,  of any  authorized  denominations,  as
requested by the Holder  surrendering the same, and of like tenor upon surrender
of the Note or Notes to be  exchanged  at the  Corporate  Trust  Office of First
Trust of New York,  National  Association,  in New York,  New York or such other
office or agency as may be designated by the Company from time to time.


                                    A-4

<PAGE>



      The  Company  shall  not  be  required  to  execute  or  provide  for  the
registration  of transfer of or the  exchange of this Note during a period of 15
days  immediately  preceding  the date notice is given  calling this Note or any
part hereof for redemption, except with respect to the unredeemed portion of any
Note being redeemed in part.

      No service charge shall be made for any such  registration  of transfer or
exchange,  but the Company may require  payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

      Prior to due presentment of this Note for  registration  of transfer,  the
Company,  the  Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Note is  registered  as the absolute  owner hereof for
all purposes,  whether or not this Note be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

      The  Indenture  and  this  Note  shall be  governed  by and  construed  in
accordance with the laws of the State of New York.

      As used  herein  "Business  Day" means any day,  other than a Saturday  or
Sunday,  which is not a day on which banking  institutions or trust companies in
The City of New York,  New York or other city in which is located  any office or
agency  maintained  for the payment of the principal of, or premium,  if any, or
interest on this Note, are generally  authorized or required by law,  regulation
or executive order to remain closed. All other terms used in this Note which are
defined  in the  Indenture  shall  have  the  meanings  assigned  to them in the
Indenture.

      As provided in the Indenture,  no recourse shall be had for the payment of
the principal of, premium,  if any, or interest on any  Securities,  or any part
thereof,  or for any claim based thereon or otherwise in respect thereof,  or of
the  indebtedness  represented  thereby,  or upon any  obligation,  covenant  or
agreement under the Indenture,  against,  and no personal  liability  whatsoever
shall attach to, or be incurred by, any  incorporator,  shareholder,  officer or
director,  as such, past, present or future of the Company or of any predecessor
or  successor   corporation  (either  directly  or  through  the  Company  or  a
predecessor or successor  corporation),  whether by virtue of any constitutional
provision,  statute or rule of law, or by the  enforcement  of any assessment or
penalty  or  otherwise;  it  being  expressly  agreed  and  understood  that the
Indenture and all the Securities are solely  corporate  obligations and that any
such personal  liability is hereby  expressly waived and released as a condition
of, and as part of the consideration for, the execution of the Indenture and the
issuance of the Securities.

      Unless the certificate of  authentication  hereon has been executed by the
Trustee or an Authenticating  Agent by manual signature,  this Note shall not be
entitled to any benefit under the  Indenture or be valid or  obligatory  for any
purpose.


                                    A-5

<PAGE>



      IN WITNESS  WHEREOF,  the Company has caused  this  instrument  to be duly
executed under its corporate seal to be hereunto affixed and attested.

                                    PUBLIC SERVICE COMPANY OF COLORADO



                                    By:___________________________________
                                          Senior Vice President


Attest:

______________________________
      Secretary


                         CERTIFICATE OF AUTHENTICATION

      This is one of the Securities of the series designated therein referred to
in the within-mentioned Indenture.

Dated:_______________

FIRST TRUST OF NEW YORK,      OR          FIRST TRUST OF NEW YORK,
NATIONAL ASSOCIATION                      NATIONAL ASSOCIATION,
  as Trustee                                 as Trustee



By:__________________________             By:  [                     ],
         Authorized Officer                    as Authenticating Agent


                                          By:_____________________________
                                               Authorized Officer

      Unless this  certificate is presented by an authorized  representative  of
The Depository Trust Company, a New York corporation  ("DTC"), to the Company or
its  agent  for  registration  of  transfer,   exchange,  or  payment,  and  any
certificate issued is registered in the name of Cede & Co. or in such other name
as is requested by an authorized  representative of DTC (and any payment is made
to  Cede  & Co.  or to  such  other  entity  as is  requested  by an  authorized
representative  of DTC), ANY TRANSFER,  PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE  BY OR TO ANY PERSON IS  WRONGFUL  inasmuch  as the  registered  owner
hereof, Cede & Co., has an interest herein.

      This  Note may not be  transferred  or  exchanged,  nor may any  purported
transfer be registered,  except (i) this Note may be  transferred in whole,  and
appropriate  registration  of transfer  effected,  if such transfer is by Cede &
Co., as nominee for The  Depository  Trust  Company (the  "Depositary"),  to the
Depositary,  or by the Depositary to another nominee thereof,  or by any nominee
of the  Depositary to any other  nominee  thereof,  or by the  Depositary or any
nominee thereof to any successor  securities  depositary or any nominee thereof;
and (ii) this Note may be  exchanged  for  definitive  Notes  registered  in the
respective  names of the beneficial  holders  hereof,  and  thereafter  shall be
transferable  without  restrictions  if: (A) the  Depositary,  or any  successor
securities  depositary,  shall have notified the Company and the Trustee that it
is unwilling or unable to continue to act as securities  depositary with respect
to this Note or the Company becomes aware that the Depositary has ceased to be a
clearing agency registered under the Securities Exchange Act of 1934,

                                    A-6

<PAGE>



as amended, and in any such case the Trustee shall not have been notified by the
Company  within  ninety  (90) days of the  identity  of a  successor  securities
depositary  with respect to this Note;  (B) the Company shall have  delivered to
the Trustee an  Officer's  Certificate  to the effect that this Note shall be so
exchangeable  on and  after a date  specified  therein;  or  (C)(1)  an Event of
Default shall have occurred and be continuing,  (2) the Trustee shall have given
notice of such Event of Default  pursuant to Section 1102 of the  Indenture  and
(3) there shall have been delivered to the Company and the Trustee an Opinion of
Counsel to the effect that the interests of the  beneficial  owners of this Note
in respect thereof will be materially impaired unless such owners become Holders
of definitive Notes.

                             ________________

   FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto

- --------------------------------------------------------------------------------

     [please insert social security or other identifying number of assignee]

- --------------------------------------------------------------------------------

            [please print or typewrite name and address of assignee]

- --------------------------------------------------------------------------------

the  within  Note  of  PUBLIC  SERVICE  COMPANY  OF  COLORADO  and  does  hereby
irrevocably constitute and appoint ________________,  Attorney, to transfer said
Note  on  the  books  of  the   within-mentioned   Company,with  full  power  of
substitution in the premises.



Dated:__________________



           __________________________________________________________
      Notice:  The signature to this assignment must correspond with the name as
      written upon the face of the Note in every particular  without  alteration
      or enlargement or any change whatsoever.


                                    A-7

<PAGE>



                           OPTION TO ELECT REPAYMENT

The  undersigned  hereby  irrevocably  request(s) and instruct(s) the Company to
repay this Note (or portion hereof  specified  below) pursuant to its terms at a
price equal to 100% of the principal  amount to be repaid,  together with unpaid
interest  accrued  hereon  to  the  Repayment  Date,  to  the  undersigned,   at
_______________________________________________________________________________
         (Please print or typewrite name and address of the undersigned)

      For this Note to be repaid,  the  Trustee  must  receive at its  Corporate
Trust  Office in New York,  New York not more than 60 nor less than 30  calendar
days  prior  to the  Repayment  Date,  this  Note  with  this  "Option  to Elect
Repayment" form duly completed.

      If less than the  entire  principal  amount of this Note is to be  repaid,
specify the portion  hereof (which shall be increments of $1,000  (provided that
any remaining  principal  amount hereof shall be at least  $100,000))  which the
Holder  elects to have  repaid and  specify the  denomination  or  denominations
(which  shall be a minimum of  $100,000) of the Notes to be issued to the Holder
for the  portion  of this  Note not being  repaid  (in the  absence  of any such
specification, one such Note will be issued for the portion not being repaid).


Principal Amount
to be Repaid:  $____________                  _________________________________

Date:_______________________                  Notice:  The  signature(s) on this
                                              Option   to  Elect Repayment  must
                                              correspond   with  the  name(s) as
                                              written upon the face of this Note
                                              in   every   particular,   without
                                              alteration  or  enlargement or any
                                              change whatsoever.



                                    A-8

<PAGE>





                                                                    SCHEDULE A

                            SUPPLEMENTAL INDENTURES


     Date of                                                          Principal
  Supplemental                                      Principal           Amount
    Indenture            Series of Bonds          Amount Issued      Outstanding
    ---------            ---------------          -------------      -----------
   
November 1, 1993           Series No. 1           $134,500,000      $134,500,000

January 1, 1994     Series No. 2 due 2001 and     $102,667,000      $102,667,000
                      Series No. 2 due 2024       $110,000,000      $110,000,000

September 2, 1994         Appointment of              None              None
                        Successor Trustee

May 1, 1996           Series No. 3 due 2006       $125,000,000      $125,000,000




                                    I-1

<PAGE>


                                                                    SCHEDULE B

                            DESCRIPTION OF PROPERTY







                                    II-1



                                                                       Exhibit 5

                         LeBoeuf, Lamb, Greene & MacRae
                                     L.L.P.
                              125 West 55th Street
                             New York, NY 10019-5389


                                          October 22, 1996


Public Service Company of Colorado
1225 17th Street
Denver, Colorado  80202

      Re:  Public Service Company of Colorado --
            $400,000,000 in Aggregate Principal Amount of
            First Collateral Trust Bonds
            ---------------------------------------------
Dear Sirs:

            We are acting as counsel for Public Service Company of Colorado (the
"Company")  in  connection  with  the  proposed  issuance  and  sale  of  up  to
$400,000,000 in aggregate  principal amount of First Collateral Trust Bonds (the
"Securities")  of the  Company,  to be  issued in one or more  separate  series,
pursuant  to an  Indenture  dated as of  October  1,  1993,  and the  indentures
supplemental  thereto,  including  one or  more  supplemental  indentures  to be
entered  into  in  connection   with  the  issuance  of  the   Securities   (the
"Indenture"),  between  the  Company  and  First  Trust  of New  York,  National
Association, as successor trustee thereunder (the "Trustee").

            As  such  counsel,   we  have  examined  such   corporate   records,
certificates  and  other  documents  as we  have  considered  necessary  for the
purposes of this opinion.  In such examination,  we have assumed the genuineness
of  all  signatures,  the  authenticity  of  all  documents  submitted  to us as
originals,  the conformity to the original documents of all documents  submitted
to us as copies and the authenticity of the originals of such latter  documents.
As to any facts material to our opinion,  we have,  when relevant facts were not
independently established,  relied upon the aforesaid records,  certificates and
documents.

            Upon the  basis of the  foregoing  examination  and  subject  to the
limitations contained herein, we are of the opinion that:


<PAGE>


Public Service Company of Colorado
October 22, 1996
Page 2


                  (a) when (i) the  Registration  Statement  that is being filed
      with the Securities and Exchange Commission with respect to the Securities
      has become  effective  under the  Securities  Act of 1933, as amended (the
      "Act") and (ii) the  Prospectus  relating to the  Securities has been duly
      supplemented with respect to the Securities of a particular  series,  and,
      as so  supplemented,  duly filed under the Act, no further  authorization,
      consent or approval by any  regulatory  authority will be required for the
      valid issuance and sale of the Securities of such series (except under the
      so-called  "blue-sky" or securities laws of the several states,  as to the
      applicability of which we do not express an opinion);

                  (b) when the Board of  Directors  of the Company has  approved
      the terms and conditions of the Supplemental  Indenture  creating a series
      of Securities  and the terms and  conditions  relating to the issuance and
      sale of the Securities of such series,  the Securities of such series will
      have been duly authorized by the Company;

                  (c) upon the  execution  and  filing  with the  Trustee of the
      proper papers with respect to the Securities of a particular  series,  the
      Securities  of such  series  will  be  issuable  under  the  terms  of the
      Indenture; and

                  (d) upon the  execution,  authentication  and  delivery of the
      Securities of each particular  series in accordance with the corporate and
      governmental  authorizations  and the  instruments  referred to above and,
      upon receipt of payment  therefor,  the  Securities of such series will be
      legally issued and binding obligations of the Company and will be entitled
      to the benefits  provided by the Indenture on a parity with the Securities
      of other series which may hereafter be issued  thereunder  pursuant to the
      terms thereof.

            We consent to the filing of this  opinion with and as a part of said
Registration  Statement  and  the use of our  name  therein  and in the  related
Prospectus  under  the  caption  "Legal  Opinions"  and  in  any  amendments  or
supplements to the Registration Statement and Prospectus.

                                Very truly yours,

                              /s/LeBoeuf, Lamb, Greene & MacRae, L.L.P



                                                                   Exhibit 12


                       PUBLIC SERVICE COMPANY OF COLORADO
                                AND SUBSIDIARIES

                  COMPUTATION OF RATIO OF CONSOLIDATED EARNINGS
                          TO CONSOLIDATED FIXED CHARGES

<TABLE>
<CAPTION>


                                             Six Months
                                               Ended
                                              June 30,                Year Ended December 31,
                                               1996        1995        1994      1993         1992       1991
                                               ----        ----        ----      ----         ----       ----
                                                                (Thousands of Dollars, except ratios)
<S>                                         <C>          <C>        <C>       <C>         <C>        <C>

Fixed charges:

  Interest on long-term debt                $  43,782    $ 85,832    $89,005  $ 98,089    $ 92,581   $ 81,666
  Interest on borrowings against corporate-
    owned life insurance contracts..........   19,286      34,717     29,786    25,333      18,312      8,144
  Other interest............................    9,947      23,392     14,235     9,445      12,357     14,574
  Amortization of debt discount and expense
    less premium ...........................    1,842       3,278      3,126     2,018       1,790      1,827
  Interest component of rental expense......    5,379       6,729      6,888     6,824       7,904      6,892
                                                -----       -----      -----     -----       -----      -----

     Total ................................. $ 80,236    $153,948   $143,040  $141,709    $132,944   $113,103
                                             ========    ========   ========  ========    ========   ========


Earnings (before fixed charges and taxes on income):
  Net income...............                  $ 98,966    $178,856   $170,269  $157,360     $136,623  $149,693
  Fixed charges as above....................   80,236     153,948    143,040   141,709      132,944   113,103
  Provisions for Federal and state taxes
   on income, net of investment tax credit
    amortization............................   57,459      95,357     48,500    60,994       53,149    69,288
                                               ------      ------     ------    ------       ------    ------

     Total.................................. $236,661     $428,161  $361,809  $360,063     $322,716  $332,084
                                             ========     ========  ========  ========     ========  ========

Ratio of earnings to fixed charges               2.95         2.78      2.53      2.54         2.43      2.94
                                             ========     ========   =======   =======     ========  ========
</TABLE>



                                                                      EXHIBIT 15
October 22, 1996

Public Service Company of Colorado

We are aware  that  Public  Service  Company of  Colorado  has  incorporated  by
reference in this  registration  statement,  pertaining to the  registration  of
$400,000,000 of First  Collateral  Trust Bonds, in one or more series of secured
medium-term  notes,  its Form 10-Q's for the  quarters  ended March 31, 1996 and
June 30, 1996,  which include our reports dated May 10, 1996 and August 6, 1996,
respectively, covering the unaudited consolidated condensed financial statements
contained therein. Pursuant to Regulation C of the Securities Act of 1933, these
reports are not  considered  a part of the  registration  statement  prepared or
certified  by our Firm or a report  prepared or certified by our Firm within the
meaning of Sections 7 and 11 of the Act.


                                ARTHUR ANDERSEN LLP



                                            

                                                                   EXHIBIT 23(a)

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent  public  accountants,  we hereby consent to the  incorporation by
reference in this registration  statement of our report dated February 15, 1996,
included in Public  Service  Company of Colorado's  Form 10-K for the year ended
December 31, 1995, and to all references to our Firm included in such Form 10-K.


                                                     ARTHUR ANDERSEN LLP

Denver, Colorado
October 22, 1996


                                                                      Exhibit 25

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549
                                _______________

                                   FORM T - 1

                    STATEMENT OF ELIGIBILITY UNDER THE TRUST
                     INDENTURE ACT OF 1939 OF A CORPORATION
                          DESIGNATED TO ACT AS TRUSTEE
                                _______________

                CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY
             OF A TRUSTEE PURSUANT TO SECTION 305 (b) (2) _________

                  FIRST TRUST OF NEW YORK, NATIONAL ASSOCIATION
               (Exact name of trustee as specified in its charter)

                                   13-3781471
                               (I. R. S. Employer
                               Identification No.)

           100 Wall Street, New York, NY                 10005
      (Address of principal executive offices)        (Zip Code)

                                _______________

                         Dennis J. Calabrese, President
                  First Trust of New York, National Association
                           100 Wall Street, 16th Floor
                               New York, NY 10005
                            Telephone: (212) 361-2506
            (Name, address and telephone number of agent for service)
                                 ______________
                       PUBLIC SERVICE COMPANY OF COLORADO
               (Exact name of obligor as specified in its charter)

           Colorado                                   84-0296600
 (State or other jurisdiction of                 (I. R. S. Employer
 incorporation or organization)                  Identification No.)

           1225 17th Street
           Denver, Colorado                              80202
(Address of principal executive offices)               (Zip Code)
                                _______________
                          FIRST COLLATERAL TRUST BONDS
                       (Title of the indenture securities)

<PAGE>



Item 1.     General Information.

      Furnish the following information as to the trustee - -

      (a)   Name and address of each examining or supervising authority to
            which it is subject.

                        Name                                Address
                        ----                                -------
              Comptroller of the Currency               Washington, D. C.

      (b)   Whether it is authorized to exercise corporate trust powers.

            Yes.

Item 2.     Affiliations with the Obligor.

      If  the  obligor  is an  affiliate  of the  trustee,  describe  each  such
affiliation.

            None.

Item 16.    List of Exhibits.

     Exhibit 1. Articles of  Association  of First  Trust of New York,  National
                Association,  incorporated  herein  by reference to Exhibit 1 of
                Form T-1, Registration No. 33-83774.

     Exhibit 2. Certificate of Authority to Commence Business for First Trust of
                New  York,  National   Association,   incorporated   herein   by
                reference to Exhibit 2 of Form T-1, Registration No. 33-83774.

     Exhibit 3. Authorization  of the Trustee to exercise corporate trust powers
                for First Trust  of New York, National Association, incorporated
                herein by reference  to  Exhibit 3 of Form T-1, Registration No.
                33-83774.

     Exhibit 4. By-Laws  of  First  Trust  of  New  York,  National Association,
                Incorporated   herein   by  reference  to Exhibit 4 of Form T-1,
                Registration No. 33-55851.

     Exhibit 5. Not applicable.

     Exhibit 6. Consent  of  First  Trust  of New  York,  National  Association,
                required  by  Section  321(b)  of  the  Act, incorporated herein
                by reference to Exhibit 6 of Form T-1, Registration No.33-83774.

     Exhibit 7. Report  of   Condition  of  First  Trust of New  York,  National
                Association,  as  of  the  close  of  business on June 30, 1996,
                published pursuant to law or the requirements of its supervising
                or examining authority.

     Exhibit 8. Not applicable.

     Exhibit 9. Not applicable.





                                    SIGNATURE


            Pursuant to the  requirements of the Trust Indenture Act of 1939, as
amended, the trustee, First Trust of New York, National Association,  a national
banking association  organized and existing under the laws of the United States,
has duly caused this  statement of eligibility to be signed on its behalf by the
undersigned,  thereunto duly authorized,  all in the City of New York, and State
of New York, on the 21st day of October, 1996.

                                    FIRST TRUST OF NEW YORK,
                                        NATIONAL ASSOCIATION



                                    By:   /s/ Catherine F. Donohue
                                          ________________________________   
                                          Catherine F. Donohue
                                          Vice President



<PAGE>


                                                                       Exhibit 7


                         First Trust of New York, N. A.
                        Statement of Financial Condition
                                 As of 06/30/96

                                   ($000's)

                                                 06/30/96
                                                 --------
Assets
   Cash and Due From Depository Institutions      $29,167
   Federal Reserve Stock                            3,658
   Fixed Assets                                       707
   Intangible Assets                               82,730
   Other Assets                                     8,084
                                                    -----
      Total Assets                               $124,346
                                                 ========


Liabilities
   Other Liabilities                                6,207
                                                    -----
   Total Liabilities                                6,207

Equity
   Common and Preferred Stock                       1,000
   Surplus                                        120,932
   Undivided Profits                               (3,793)
                                                   ------ 
      Total Equity Capital                        118,139
                                                  

Total Liabilities and Equity Capital             $124,346
                                                 ========
================================================================================


To the  best of the  undersigned's  determination,  as of this  date  the  above
financial information is true and correct.

First Trust of New York, N. A.



By:   /s/ Catherine F. Donohue
    __________________________
      Vice President

Date:  October 21, 1996


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