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                                                                     Exhibit 4.6

REGISTERED                                                            REGISTERED

                   Illinois Commerce Commission ID Number 5994

     THIS NOTE IS A GLOBAL NOTE REGISTERED IN THE NAME OF THE DEPOSITARY
(REFERRED TO HEREIN) OR A NOMINEE THEREOF AND, UNLESS AND UNTIL IT IS EXCHANGED
IN WHOLE FOR THE INDIVIDUAL NOTES REPRESENTED HEREBY AS PROVIDED IN THE
INDENTURE REFERRED TO BELOW, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE
BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW
YORK), TO THE TRUSTEE FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND
ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                          SENIOR NOTE, 6.125% DUE 2028

CUSIP: 153663BJ7                        NUMBER: 1

ORIGINAL ISSUE DATE: December 22, 1998  PRINCIPAL AMOUNT: $60,000,000

INTEREST RATE: 6.125%                   MATURITY DATE: December 15, 2028

     CENTRAL ILLINOIS PUBLIC SERVICE COMPANY, a corporation of the State of
Illinois (the "COMPANY"), for value received hereby promises to pay to CEDE &
CO. or registered assigns, the principal sum of SIXTY MILLION DOLLARS
($60,000,000) on the Maturity Date set forth above, and to pay interest thereon
from December 22, 1998 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, semi-annually in arrears on the
June 15 and December 15 in each year, commencing June 15, 1999, at the per annum
Interest Rate set forth above, until the principal hereof is paid or made
available for payment. No interest shall accrue on the Maturity Date, so long as
the principal amount of this Note is paid on the Maturity Date. The interest so
payable and punctually paid or duly provided for on any such Interest Payment
Date (except for interest payable on the Maturity Date set forth above or, if
applicable, upon redemption or acceleration) will, as provided in the

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Indenture (as defined below), be paid to the Person in whose name this Note is
registered at the close of business on the Regular Record Date for such
interest, which shall be the May 31 or November 30, as the case may be, next
preceding such Interest Payment Date; provided that the first Interest Payment
Date for any part of this Note, the Original Issue Date of which is after a
Regular Record Date but prior to the applicable Interest Payment Date, shall be
the Interest Payment Date following the next succeeding Regular Record Date; and
provided that interest payable on the Maturity Date set forth above or, if
applicable, upon redemption or acceleration, shall be payable to the Person to
whom principal shall be payable. Except as otherwise provided in the Indenture,
any such interest not so punctually paid or duly provided for shall forthwith
cease to be payable to the Holder on such Regular Record Date and shall be paid
to the Person in whose name this Note 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 whereof shall be given to Noteholders not more than fifteen
days or fewer than ten days prior to such Special Record Date. Payment of the
principal of and interest and premium on this Note shall be payable pursuant to
Section 2.12(a) of the Indenture.

     This Note is a Global Note in respect of a duly authorized issue of Senior
Notes, 6.125% Due 2028 (the "NOTES OF THIS SERIES", which term includes any
Global Notes representing such Notes) of the Company issued and to be issued
under an Indenture dated as of December 1, 1998, between the Company and The
Bank of New York, as trustee (the "TRUSTEE", which term includes any successor
Trustee under the Indenture) and indentures supplemental thereto (collectively,
the "INDENTURE"). Under the Indenture, one or more series of notes may be issued
and, as used herein, the term "Notes" refers to the Notes of this Series and any
other outstanding series of Notes. Reference is hereby made to the Indenture for
a more complete statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Noteholders
and of the terms upon which the Notes are and are to be authenticated and
delivered. This Note has been issued in respect of the series designated on the
first page hereof, limited in aggregate principal amount to $60,000,000.

     Prior to the Release Date (as hereinafter defined), the Notes will be
secured by first mortgage bonds (the "SENIOR NOTE FIRST MORTGAGE BONDS")
delivered by the Company to the Trustee for the benefit of the Holders of the
Notes, issued under the Indenture of Mortgage or Deed of Trust, dated October 1,
1941, from the Company to U.S. Bank Trust National Association, as successor
trustee (the "MORTGAGE TRUSTEE"), and F. Sgaraglino, as successor co-trustee, as
supplemented and modified (collectively, the "FIRST MORTGAGE"). Reference is
made to the First Mortgage and the Indenture for a description of the rights of
the Trustee as holder of the Senior Note First Mortgage Bonds, the property
mortgaged and pledged, the nature and extent of the security and the rights of
the holders of first mortgage bonds, under the First Mortgage and the rights of
the Company and of the Mortgage Trustee in respect thereof, the duties and
immunities of the Mortgage Trustee and the terms and conditions upon which the
Senior Note First Mortgage Bonds are secured and the circumstances under which
additional first mortgage bonds may be issued.

     From and after such time as all first mortgage bonds (other than Senior
Note First Mortgage Bonds) issued under the First Mortgage have been retired
through payment, redemption or otherwise at, before or after the maturity
thereof (the "Release Date"), the Senior Note First Mortgage Bonds shall cease
to secure the Notes in any manner. In certain


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circumstances prior to the Release Date as provided in the Indenture, the
Company is permitted to reduce the aggregate principal amount of a series of
Senior Note First Mortgage Bonds held by the Trustee, but in no event prior to
the Release Date to an amount less than the aggregate outstanding principal
amount of the series of Notes initially issued contemporaneously with such
Senior Note First Mortgage Bonds.

     Each Note of this Series shall be dated and issued as of the date of its
authentication by the Trustee and shall bear an Original Issue Date. Each Note
issued upon transfer, exchange or substitution of such Note shall bear the
Original Issue Date of such transferred, exchanged or substituted Note, as the
case may be.

     Each Note of this Series will be redeemable, in whole or in part, at the
option of the Company at any time at a redemption price equal to the greater of
(i) 100% of the principal amount thereof and (ii) the sum of the present values
of the remaining scheduled payments of principal and interest that the Company
has not yet made on the Note (not including any portion of such payments of
interest accrued as of the date of redemption) discounted to the redemption date
on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day
months) at the Adjusted Redemption Treasury Rate (as defined below) plus 15
basis points, plus accrued interest thereon to the date of redemption. The
Company must provide the holders of each Note of this Series to be redeemed with
a notice of redemption at least 30 and not more than 60 days before the
redemption date.

     "Adjusted Redemption Treasury Rate" means, with respect to any redemption
date, the annual rate equal to the semi-annual equivalent yield to maturity or
interpolated (on a 30/360 day count basis) yield to maturity of the Comparable
Redemption Treasury Issue, assuming a price for the Comparable Redemption
Treasury Issue (expressed as a percentage of its principal amount) equal to the
Comparable Redemption Treasury Price for such redemption date.

     "Comparable Redemption Treasury Issue" means, with respect to each Note to
be redeemed, the United States Treasury security selected by the Quotation Agent
as having a maturity comparable to the remaining term of such Note to be
redeemed that would be utilized at the time of selection and in accordance with
customary financial practice in pricing new issues of corporate debt securities
of comparable maturity to the remaining term of such Note.

     "Comparable Redemption Treasury Price" means, with respect to any
redemption date, (i) the average of the Redemption Reference Treasury Dealer
Quotations for such redemption date, after excluding the highest and lowest such
Redemption Reference Treasury Dealer Quotations (unless there is more than one
highest or lowest quotation, in which case only one such highest and/or lowest
quotation shall be excluded), or (ii) if the Quotation Agent obtains fewer than
four such Redemption Reference Treasury Dealer Quotations, the average of all
such Redemption Reference Treasury Dealer Quotations.

     "Quotation Agent" means one of the Redemption Reference Treasury Dealers
appointed as such agent by the Company.

     "Redemption Reference Treasury Dealer" means Lehman Brothers Inc. and four
other primary U.S. Government securities dealers in New York City selected by
the Company.


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     "Redemption Reference Treasury Dealer Quotations" means, with respect to
each Redemption Reference Treasury Dealer and any redemption date, the offer
price for the Comparable Redemption Treasury Issue (expressed in each case as a
percentage of its principal amount) for settlement on the redemption date quoted
in writing to the Quotation Agent by such Redemption Reference Treasury Dealer
at 5:00 p.m., New York City time, on the third business day preceding such
redemption date.

     Interest payments for this Note shall be computed and paid on the basis of
a 360-day year of twelve 30-day months (and for any partial periods shall be
calculated on the basis of the number of days elapsed in a 360-day year of
twelve 30-day months). If any Interest Payment Date or date on which the
principal of this Note is required to be paid is not a Business Day, then
payment of principal, premium or interest need not be made on such date but may
be made on the next succeeding Business Day with the same force and effect as if
made on such Interest Payment Date or date on which the principal of this Note
is required to be paid and, in the case of timely payment thereof, no interest
shall accrue for the period from and after such Interest Payment Date or the
date on which the principal of this Note is required to be paid.

     The Company, at its option, and subject to the terms and conditions
provided in the Indenture, will be discharged from any and all obligations in
respect of the Notes (except for certain obligations including obligations to
register the transfer or exchange of Notes, replace stolen, lost or mutilated
Notes, maintain paying agencies and hold monies for payment in trust, all as set
forth in the Indenture) if the Company deposits with the Trustee money, U.S.
Government Obligations which through the payment of interest thereon and
principal thereof in accordance with their terms will provide money, or a
combination of money and U.S. Government Obligations, in any event in an amount
sufficient, without reinvestment, to pay all the principal of and any premium
and interest on the Notes on the dates such payments are due in accordance with
the terms of the Notes.

     If an Event of Default shall occur and be continuing, the principal of and
interest on the Notes may be declared due and payable in the manner and with the
effect provided in the Indenture and, upon such declaration, the Trustee shall
demand the redemption of the Senior Note First Mortgage Bonds to the extent
provided in the Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modifications of the rights and obligations of the
Company and the rights of the Noteholders under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of not less than a
majority in principal amount of the outstanding Notes. 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 thereof
whether or not notation of such consent or waiver is made upon this Note.

     As set forth in and subject to the provisions of the Indenture, no Holder
of any Notes will have any right to institute any proceeding with respect to the
Indenture or for any remedy thereunder unless such Holder shall have previously
given to the Trustee written notice of a continuing Event of Default with
respect to such Notes, the Holders of not less than a majority in principal
amount of the outstanding Notes affected by such Event of Default shall have
made


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written request and offered reasonable indemnity to the Trustee to institute
such proceeding as Trustee and the Trustee shall have failed to institute such
proceeding within 60 days; provided that such limitations do not apply to a suit
instituted by the Holder hereof for the enforcement of payment of the principal
of and any premium or interest on this Note on or after the respective due dates
expressed here.

     No reference herein to the Indenture and to provisions of this Note or of
the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of and any premium and interest
on this Note at the times, places and rates and the coin or currency prescribed
in the Indenture.

     As provided in the Indenture and subject to certain limitations therein set
forth, this Note may be transferred only as permitted by the legend hereto and
the provisions of the Indenture.

     The Indenture and the Notes shall be governed by, and construed in
accordance with, the laws of the State of New York without regard to conflicts
of law principles thereof.

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

     All terms used in this Note which are defined in the Indenture shall have
the meanings assigned to them in the Indenture unless otherwise indicated
herein.


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     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                        CENTRAL ILLINOIS PUBLIC SERVICE
                                        COMPANY


                                        By: /s/ J. T. Birkett
                                           -------------------------------------
                                                  J. T. Birkett

                                        Title: Vice President
                                              ----------------------------------

                                        Attest: /s/ J. A. Tisckos
                                               ---------------------------------
                                                  J. A. Tisckos

                                        Title: Assistant Secretary
                                              ----------------------------------

TRUSTEE'S CERTIFICATE
OF AUTHENTICATION

Dated: December 22, 1998

This Note is one of the Notes of the series herein
designated, described or provided for in the within-
mentioned Indenture.

The Bank of New York, AS TRUSTEE

By: /s/ Robert J. [Illegible]
   -------------------------------
          AUTHORIZED SIGNATORY


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                                  ABBREVIATIONS

     The following abbreviations, when used in the inscription on the face of
this instrument, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM -- as tenants in common              UNIF GIFT
                                             MIN ACT - _____ Custodian ______
                                                       (Cust)          (Minor)
TEN ENT -- as tenants by the
entireties                                      Under Uniform Gifts to Minors

JT TEN -- as joint tenants with right
of survivorship and not as tenants in
common                                       ______________________________
                                                       State

                    Additional abbreviations may also be used
                          though not in the above list.

                                   ----------

               FOR VALUE RECEIVED the undersigned hereby sell(s),
                         assign(s) and transfer(s) unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
IDENTIFYING NUMBER OF ASSIGNEE

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                   Please print or typewrite name and address
                      including postal zip code of assignee

---------------------------------------
the within note and all rights thereunder,
hereby irrevocably constituting and appointing
attorney to transfer said note on the
books of the 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 within instrument
                                        in every particular, without alteration
                                        or enlargement or any change whatever.
                                        Signature(s) must be guaranteed by a
                                        financial institution that is a member
                                        of the Securities Transfer Agents
                                        Medallion Program ("STAMP"), the Stock
                                        Exchange Medallion Program ("SEMP") or
                                        the New York Stock Exchange, Inc.
                                        Medallion Signature Program("MSP").


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