Exhibit 4(b)(3)

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                               PUBLIC SERVICE COMPANY
                                    OF COLORADO
                                          
                                         TO
                                          
                              FIRST TRUST OF NEW YORK,
                                NATIONAL ASSOCIATION,
                                          
                                          
                                                                     as Trustee

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

                          SUPPLEMENTAL INDENTURE NO. [   ]


                     Dated as of [                            ]


                           Supplemental to the Indenture
                            dated as of October 1, 1993

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

                 Establishing the Securities of Series No._[___]
                          designated [First Collateral
                          Trust Bonds, Series No. {__}]*
                   [Secured Medium-Term Notes, Series_{___}]**

===============================================================================

*    For bonds.
**  For medium-term notes.



          SUPPLEMENTAL INDENTURE NO. [___], dated as of [__________________],
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. [___]. 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 ["First Collateral Trust Bonds, Series No. {___}"] ["Secured Medium
Term Notes, Series {___}", being a series of First Collateral Trust Bonds], such
series of Securities to be hereinafter sometimes called "Series No. [___]".

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


                                   Granting Clauses

          NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE NO. [___] 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. [___], 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 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. [___] 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. [___];


                                     -2-



                                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 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:


                                     -3-



                                     ARTICLE ONE

                            Securities of Series No. [   ]

          There are hereby established the Securities of Series No. [   ], 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 ["First
          Collateral Trust Bonds, Series No. {   }"] ["Secured Medium-Term
          Notes, Series {   }", 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. [   ] which may be authenticated and
          delivered under the Indenture.  The Securities of Series No. [   ]
          shall be initially authenticated and delivered from time to time in
          the aggregate principal amount of [up to] $[___________];

               (c)  interest on the Securities of Series No. [   ] 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 [the Securities] [each Security]*  
          of Series No. [   ] shall be payable on [   ] [such date as is 
          specified in the Officer's Certificate applicable to such Security]*;

               (e)  [the Securities of Series No. {___} shall bear interest at
          the rate of {_______} per centum ({____%}) per annum; interest shall
          accrue on the Securities of Series No. {___} from {___________}, or
          the most recent date to which interest has been paid or duly provided
          for; the Interest Payment Dates for such Securities shall be
          {___________} and {_________} in each year, commencing {_________},
          and the Regular Record Dates with respect to the Interest Payment
          Dates for such Securities shall be {__________} and 

- ------------------------
* For medium-term notes


                                     -4-



          {___________} in each year, respectively (whether or not a Business
          Day)]*; [an Officer's Certificate with respect to each Security of 
          Series No. {___} shall specify the rate at which such Security of 
          Series No. [___] shall bear interest, the date from which interest 
          shall accrue, the Interest Payment Dates if other than ______{____} 
          and _______ {____} of each year and the Regular Record Dates with 
          respect to the Interest Payment Dates if other than ______ {___} and 
          _______ {___}]**;

               (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. [___] 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)  the Securities of Series No. {   } [shall not be redeemable
          prior to _____________________.  On and after that date, the 
          Securities of Series No. {   } ]  


- ------------------------------- 
*   For bonds.
**  For medium-term notes.


                                     -5-



[shall be redeemable in whole or in part, at the option of the Company, during
the period, at the prices and upon the conditions and terms as set forth below:


                    If Redeemed in the             If Redeemed in the
                  12 Month Period Ending         12 Month Period Ending
                    on the last day of             on the last day of

              _____________       Premium    _____________       Premium
                                                        
              20__                  __%      20__                  __%
              20__                  __%      20__                  __%

              20__                  __%      20__                  __%

              20__                  __%      20__                  __%

              20__                  __%      20__                  __%
              20__                  __%      20__                  __%



          [each Security of Series No. {   } shall be redeemable only if and to
the extent specified in the Officer's Certificate applicable to such Security of
Series No. {   }];* 

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

               (i)  [not applicable] [the Securities of Series No. {   } 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;


- ------------------------------
*  For medium-term notes.


                                     -6-



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

               (o)  not applicable;

               (p)  not applicable;

               (q)  [each Security of Series No. {   } 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. {   }
          shall not be transferable or exchangeable, nor shall any purported
          transfer be registered, except as follows:

               (i)  a Security of Series No. {   } 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

               (ii) a Security of Series No. {   } 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. {   } 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. {   };

                    (B)  The Company shall have delivered to the Trustee a
               Company Order to the effect that such Security of Series No. 
               {   } 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 


                                     -7-



               Counsel to the effect that the interests of the beneficial owners
               of such Security of Series No. {   } 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. [   ] [, or any
          Tranche thereof;] 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. {___} to have
          been satisfied and discharged prior to the Maturity of such Security
          of Series No. {___}, 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. {___} on such date stating
          (A)(1) the aggregate principal amount of such Security of Series No.
          {___} 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. {___}) 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. {___} 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. {___} 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 consequences to it resulting from the satisfaction and
          discharge of the Company's indebtedness in respect of such Security of
          Series No. {   }. 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. {   } 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. {   } 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. {   }, as the case may be (such
          information to be set 


                                     -8-



          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. {   } 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. {   } 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. {   } 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. {   } 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. {   } 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. {   }
          pursuant to such Section.]

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


                                     -9-



                                     ARTICLE TWO

                               Miscellaneous Provisions

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

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

                                       PUBLIC SERVICE COMPANY OF
                                        COLORADO



                                       By:
                                          ------------------------------------
                                          [Name]
                                          Executive Vice President


                                       FIRST TRUST OF NEW YORK
                                        NATIONAL ASSOCIATION, Trustee



                                       By:
                                          ------------------------------------
                                          [Name]
                                         Vice President







                                    -10-




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



          On the _____ day of __________ 1997, before me personally came
_________________ _____________, to me known, who, being by me duly sworn, did
depose and say that [    ] is a _________________________ of Public Service
Company of Colorado, one of the corporations described in and which executed the
foregoing instrument; and that [     ] signed [     ] name thereto by authority
of the Board of Directors of said corporation.




                                       --------------------------------------
                                                    Notary Public













                                    -11-



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



          On the _____ day of ______________, 1997, before me personally came
_________________________, to me known, who, being by me duly sworn, did depose
and say that [     ] is a _________________________ of First Trust of New York,
National Association, the national banking association described in and which
executed the foregoing instrument; and that [     ] signed [     ] name thereto
by authority of the Board of Directors of said national banking corporation.




                                       --------------------------------------
                                                    Notary Public













                                    -12-



                                                                    EXHIBIT A-1
                                   FORM OF SECURITY

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


                      PUBLIC SERVICE COMPANY OF COLORADO

                 First Collateral Trust Bond, Series No. {  }




[Original Interest Accrual Date:]                Regular Record Dates:
Interest Rate: 
Default Rate:  
Stated Maturity:    
Interest Payment Dates:

                                                 {OID:  Yes __ No__
                                                 Total Amount of OID (%):
                                                 Yield to Maturity (%):
                                                 Initial Accrual Period OID (%):
                                                 (Constant - Yield Method)}

                     [This Security 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 Interest Accrual 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 


                                     A-1



specified above in each year, commencing with the Interest Payment Date next 
succeeding the Original Interest Accrual Date specified above, and at 
Maturity, at the Interest Rate per annum 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 Security (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.  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 
Security (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.

          Payment of the principal of [and premium, if any, on] this Security
and interest hereon at Maturity shall be made upon presentation of this Security
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
Security (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
Security 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 Security, 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 Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), 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


                                     A-2



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
Security shall be deemed to constitute the consent and agreement by the Holder
hereof to all of the terms and provisions of the Indenture.  This Security is
one of the series designated above.

          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 Security 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.

          [This Security is not subject to redemption prior to the Stated
Maturity hereof.]

          [This Security is subject to redemption at any time on or after
______, as a whole at any time or from time to time in part, at the option of
the Company, at a redemption price equal to the principal amount hereof, plus
accrued interest to the date fixed for redemption, together with the applicable
premium, equal to a percentage of the principal amount hereof, set forth in the
table below:










                                     A-3




                    If Redeemed in the             If Redeemed in the
                  12 Month Period Ending         12 Month Period Ending
                    on the last day of             on the last day of

              _____________       Premium    _____________       Premium
                                                        
              20__                  __%      20__                  __%
              20__                  __%      20__                  __%

              20__                  __%      20__                  __%

              20__                  __%      20__                  __%

              20__                  __%      20__                  __%
              20__                  __%      20__ and thereafter   __%]


          [Notwithstanding the foregoing, the Company may not, prior to _____,
redeem this Security as contemplated above as a part of, or in anticipation of,
any refunding operation by the application, directly or indirectly, of moneys
borrowed having an effective interest cost to the Company (calculated in
accordance with generally accepted financial practice) less than the effective
interest cost to the Company (similarly calculated) of this Security.]

          [Insert provisions, if any, for redemption pursuant to a sinking fund
or analogous provision or at the option of the holder.]

          [Notice of redemption shall be given by mail to the Holder of this
Security, 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 Security, 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 Security; 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 Security].

          [In the event of redemption of this Security in part only, a new
Security or Securities of this series, of like tenor, for the unredeemed portion
hereof and otherwise having the same terms as this Security 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 Security may be declared due and payable in the manner and with the effect
provided in the Indenture.


                                     A-4



          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 Security
shall be conclusive and binding upon such Holder and upon all future Holders of
this Security and of any Security 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 Security.

          As provided in the Indenture and subject to certain limitations
therein set forth, this Security 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 Security when due.

          As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security 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 


                                     A-5



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 Securities of this series are issuable only as registered
Securities, without coupons, and in denominations of $1,000 and integral
multiples thereof.  As provided in the Indenture and subject to certain
limitations therein set forth, the Securities of this series are exchangeable
for a like aggregate principal amount of Securities 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 Security or
Securities 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.

          [The Company shall not be required to execute or provide for the
registration of transfer of or the exchange of (a) Securities of this series
during a period of 15 day immediately preceding the date notice is given
identifying the serial numbers of the Securities of this series called for
redemption or (b) any Security so selected for redemption in whole or in part,
except the unredeemed portion of any Security 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 Security 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 Security is registered as the absolute
owner hereof for all purposes, whether or not this Security be overdue, and
neither the Company, the Trustee nor any such agent shall be affected by notice
to the contrary.

          The Indenture and the Securities 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 Security, are generally authorized or required by law,
regulation or executive order to remain closed.  All other terms used in this
Security 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 


                                     A-6



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 Security shall
not be entitled to any benefit under the Indenture or be valid or obligatory for
any purpose.













                                     A-7



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


                              PUBLIC SERVICE COMPANY OF
                                COLORADO



                              By:
                                  ------------------------------------------
                                  Executive 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:  [                     ]
   ----------------------                    ---------------------------
                                               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 

                                     A-8


ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., 
HAS AN INTEREST HEREIN.

          THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR MAY ANY 
PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY 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 SECURITY MAY BE EXCHANGED 
FOR DEFINITIVE SECURITIES 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 THE 
SECURITIES 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 THE SECURITIES; (B) THE COMPANY SHALL HAVE 
DELIVERED TO THE TRUSTEE AN OFFICER'S CERTIFICATE TO THE EFFECT THAT THE 
SECURITIES 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 THE SECURITIES IN RESPECT THEREOF WILL BE MATERIALLY 
IMPAIRED UNLESS SUCH OWNERS BECOME HOLDERS OF DEFINITIVE SECURITIES.

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

                                     A-9


          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 Security of PUBLIC SERVICE COMPANY OF COLORADO and does hereby
irrevocably constitute and appoint ______________________________, Attorney, to
transfer said Security 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 Security in every particular without
                              alteration or enlargement or any change
                              whatsoever.

                                     A-10


                                                                    EXHIBIT A-2

                                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 {   }
                    (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 

                                     B-1


each year, commencing with the Interest Payment Date next succeeding the 
Original Issue Date specified above, and at Maturity, at the Interest Rate 
per annum 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 
Notes 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 Security 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.

                                      B-2


          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.

          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 

                                      B-3


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.

          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 

                                      B-4


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 Notes 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 of this series 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.

          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 

                                      B-5


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 the Notes 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.

                                      B-6


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


                                        PUBLIC SERVICE COMPANY OF
                                         COLORADO



                                        By:
                                            -------------------------------
                                            Executive 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:  [         ]
   --------------------------------               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

                                     B-7


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 THE NOTES 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 THE NOTES; (B) THE COMPANY SHALL HAVE DELIVERED TO
THE TRUSTEE AN OFFICER'S CERTIFICATE TO THE EFFECT THAT THE NOTES 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 THE NOTES
IN RESPECT THEREOF WILL BE MATERIALLY IMPAIRED UNLESS SUCH OWNERS BECOME HOLDERS
OF DEFINITIVE NOTES.

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




                                     B-8


    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
                                        Security in every particular without
                                        alteration or enlargement or any
                                        change whatsoever.


                                     B-9


                           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.


                                     B-10


                                                                    SCHEDULE A


                             SUPPLEMENTAL INDENTURES


     Date of                                         Principal       Principal
  Supplemental                                        Amount           Amount
    Indenture             Series of Bonds             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

November 1, 1996   Series No. 4 due from 9 months   $250,000,000   $250,000,000
                   to 30 years from date of issue

February 1, 1997   Series No. 5 due from 9 months   $150,000,000   $100,000,000
                   to 30 years from date of issue


                                     B-11


                                                                    SCHEDULE B

                             DESCRIPTION OF PROPERTY




                                     B-12