UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM 8-K

                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934

                Date of report (Date of earliest event reported):



                                 September 30, 2004

<TABLE>
<CAPTION>

Commission File Number           Exact Name of Registrant as            IRS Employer
----------------------           Specified in Charter;                  Identification Number
                                 State of Incorporation;                ---------------------
                                 Address and Telephone Number
                                 ----------------------------
<S>                              <C>                                    <C>
1-14756                          Ameren Corporation                     43-1723446
                                 (Missouri Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222

1-2967                           Union Electric Company                 43-0559760
                                 (Missouri Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222

1-3672                           Central Illinois Public Service        37-0211380
                                 Company
                                 (Illinois Corporation)
                                 607 East Adams Street
                                 Springfield, Illinois 62739
                                 (217) 523-3600

333-56594                        Ameren Energy Generating Company       37-1395586
                                 (Illinois Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222

<PAGE>

2-95569                          CILCORP Inc.                           37-1169387
                                 (Illinois Corporation)
                                 300 Liberty Street
                                 Peoria, Illinois 61602
                                 (309) 677-5230

1-2732                           Central Illinois Light Company         37-0211050
                                 (Illinois Corporation)
                                 300 Liberty Street
                                 Peoria, Illinois 61602
                                 (309) 677-5230

1-3004                           Illinois Power Company                 37-0344645
                                 (Illinois Corporation)
                                 500 South 27th Street
                                 Decatur, Illinois 62521
                                 (217) 424-6600
</TABLE>

Check  the  appropriate  box  below  if the  Form  8-K  filing  is  intended  to
simultaneously  satisfy the filing obligation of the registrant under any of the
following provisions:

     [ ] Written  communications  pursuant to Rule 425 under the  Securities Act
(17 CFR 230.425)

     [ ] Soliciting  material pursuant to Rule 14a-12 under the Exchange Act (17
CFR 240.14a-12)

     [ ]  Pre-commencement  communications  pursuant to Rule 14d-2(b)  under the
Exchange Act (17 CFR 240.14d-2(b))

     [ ]  Pre-commencement  communications  pursuant to Rule 13e-4(c)  under the
Exchange Act (17 CFR 240.13e-4(c))



SECTION 1 - REGISTRANT'S BUSINESS AND OPERATIONS

ITEM 1.01 Entry into a Material Definitive Agreement.

     On  September  30,  2004,  the  following   described  material  definitive
agreement was entered into in conjunction with the completion of the Acquisition
(as defined in Item 5.01 below):

     o    A power purchase  agreement between Illinois Power Company ("IPC") and
          Dynegy Power Marketing,  Inc., a subsidiary of Dynegy Inc. ("Dynegy"),
          providing  for the  annual  purchase  by IPC in 2005 and 2006 of 2,800
          megawatts  of firm  capacity.  This  agreement  is  expected to supply
          approximately  70  percent  of IPC's  electric  customer  requirements
          during those two years. The text of the power purchase agreement dated
          as of September 30, 2004 is included as Exhibit 10.1.



SECTION 2 - FINANCIAL INFORMATION

ITEM 2.03 Creation of a Direct  Financial  Obligation or an Obligation  under an
Off-Balance Sheet Arrangement of a Registrant.

     On  September  30,  2004,  in  conjunction   with  the  completion  of  the
Acquisition (as defined in Item 5.01 below), the Ameren  Corporation  ("Ameren")
System  Utility  Money Pool  Agreement  was  amended to add IPC as a party.  The
Utility Money Pool Agreement provides for short-term borrowing arrangements with
and  among  Ameren's  utility  subsidiaries,  Union  Electric  Company,  Central
Illinois Public Service Company,  Central  Illinois Light Company,  AmerenEnergy
Resources  Generating  Company  (as a lender  only)  and IPC,  Ameren's  service
company subsidiary,  Ameren Services Company, and Ameren (as a lender only). The
text of the Third Amended Ameren Corporation System Utility Money Pool Agreement
dated as of September 30, 2004 is included as Exhibit 10.2.


                                      -2-

<PAGE>

     Also on September  30, 2004, a unilateral  borrowing  agreement was entered
into between Ameren,  IPC and Ameren Services  Company which enables IPC to make
short-term borrowings directly from Ameren up to an aggregate amount outstanding
at any  time of  $500  million.  Ameren  Services  Company  is  responsible  for
operation  and  administration  of the  agreement.  The  text of the  unilateral
borrowing agreement dated as of September 30, 2004 is included as Exhibit 10.3.

ITEM 2.04  Triggering  Events That  Accelerate  or  Increase a Direct  Financial
Obligation or an Obligation under an Off-Balance Sheet Arrangement.

     The  completion  of  the  Acquisition  (as  defined  in  Item  5.01  below)
constitutes  a Change of  Control  of IPC,  as  defined  in the  indenture  (the
"Indenture")  governing the 11 1/2% Mortgage Bonds due 2010 of IPC (the "11 1/2%
Bonds"). In accordance with the Indenture,  IPC is required to commence,  within
30 days  following  the  Change  of  Control,  a tender  offer to  purchase  all
outstanding  11 1/2% Bonds at a price of 101% of their  principal  amount,  plus
accrued  and unpaid  interest to the date of  purchase.  IPC intends to commence
such an offer on or before October 30, 2004.

     As a  result  of  certain  actions  taken by IPC  immediately  prior to the
completion of the Acquisition (as defined in Item 5.01 below),  IPC has notified
the  trustee  under the  Indenture  that a  Triggering  Event (as defined in the
Indenture)  has occurred with respect to the 11 1/2% Bonds.  A Triggering  Event
enables the holders of at least 25% of the  outstanding 11 1/2% Bonds to deliver
a notice to IPC requiring IPC to redeem the 11 1/2% Bonds at a redemption  price
specified in the Indenture.



SECTION 5 - CORPORATE GOVERNANCE AND MANAGEMENT

ITEM 5.01 Changes in Control of Registrant.

     On September 30, 2004,  Ameren  completed its  acquisition of IPC and a 20%
interest  in  Electric  Energy,  Inc.  ("EEI")  from  Dynegy and  certain of its
affiliates (the "Acquisition").  As a result of the Acquisition, Ameren obtained
all of the outstanding common stock, without par value, and approximately 73% of
the  total  outstanding  preferred  stock,  $50 par  value,  of IPC.  The  total
consideration  for Ameren's  acquisition of IPC and the 20% interest in EEI from
Dynegy and certain of its affiliates  was $2.3 billion  consisting of assumption
of existing IPC outstanding  indebtedness in the amount of $1.823 billion,  $100
million in cash placed into an escrow  account as  described in Item 8.01 below,
with the balance paid with cash on hand financed  through prior issuances of new
shares of Ameren common stock.

     In connection with the Acquisition,  and as more fully described in Section
5.02 below,  (i) effective as of immediately  prior to the closing,  the size of
the Board of  Directors of IPC was  increased  from 3 to 6 and Warner L. Baxter,
Gary L.  Rainwater  and  Steven R.  Sullivan  were  elected  to fill the 3 newly
created  vacancies,  (ii) effective as of the closing,  R. Blake Young, Carol F.
Graebner and Bruce A.  Williamson  resigned as members of the Board of Directors
of IPC and (iii)  effective as of immediately  following the closing,  Daniel F.
Cole,  Thomas R. Voss and David A.  Whiteley  were  elected  to fill the 3 newly
created vacancies.



ITEM 5.02 Departure of Directors or Principal  Officers;  Election of Directors;
Appointment of Principal Officers.

     On  September  30,  2004,  in  connection   with  the  Acquisition  and  in
conjunction  with an amendment  to the Bylaws of IPC as more fully  described in
Item 5.03 below,  effective as of immediately prior to the closing,  the size of
the  Board  of  Directors  of IPC was  increased  from 3 to 6 and the  following
persons, each of whom are employed by Ameren or its affiliates, were selected to
fill the 3  vacancies:  Warner  L.  Baxter,  Gary L.  Rainwater  and  Steven  R.
Sullivan.  Additionally,  on the same date and effective as of the closing,  the
following  members of the Board of  Directors of IPC  resigned:  R. Blake Young,
Carol F.  Graebner  and  Bruce A.  Willamson.  Following  the  resignations  and
effective  immediately  following the closing,  on the same date,  the following
persons, each of whom are employed by Ameren or its affiliates, were selected to
fill the 3 vacancies: Daniel F. Cole, Thomas R. Voss and David A. Whiteley.


                                      -3-

<PAGE>

In addition,  in furtherance of the Acquisition,  the following  officers of IPC
resigned as of the closing:

         Name                         Title

R. Blake Young         President
                       (principal executive officer and
                       principal operating officer)

Nicholas J. Caruso     Executive Vice President and
                       Chief Financial Officer

Peggy E. Carter        Managing Director and Controller
                       (principal accounting officer)


Mr. Shawn E. Schukar,  a Senior Vice President at IPC prior to the  Acquisition,
was appointed  Vice  President and will be the senior  operating  officer of IPC
following the Acquisition.


The  following  officers,  all  employees  of Ameren or its  subsidiaries,  were
appointed as officers of IPC as of  immediately  following  the  Acquisition  to
serve indefinitely:

<TABLE>
<CAPTION>

                                                                                      Date First Elected or
                                                                                      ---------------------
                                                       Present Position at IPC        Appointed to Present
                                                       -----------------------        --------------------
        Name              Age at October 1, 2004       and Business Experience             Position
        ----              -----------------------      -----------------------             --------
<S>                                <C>                 <C>                            <C>
Gary L. Rainwater                  58                  Chairman, President and        September 30, 2004
                                                       Director

Mr.  Rainwater began his career with Union Electric Company ("UE") in 1979 as an
engineer.  He was  elected  Vice  President -  Corporate  Planning in 1993.  Mr.
Rainwater  was elected  Executive  Vice  President  of Central  Illinois  Public
Service  Company  ("CIPS")  in  January  1997 and was named to his  position  as
President and Chief  Executive  Officer of CIPS in December 1997. He was elected
President of Ameren Energy Resources Company  ("Resources  Company") in 1999 and
Ameren Energy Generating Company ("Genco") in 2000. He was elected President and
Chief  Operating  Officer of Ameren,  UE and Ameren  Services  Company  ("Ameren
Services")  in  August  2001 at  which  time he  relinquished  his  position  as
President of Resources  Company and Genco.  In January 2003,  Mr.  Rainwater was
named  President and Chief  Executive  Officer of CILCORP Inc.  ("CILCORP")  and
Central  Illinois  Light Company  ("CILCO")  upon Ameren's  acquisition of those
companies.  Effective  January 1, 2004, Mr.  Rainwater became Chairman and Chief
Executive Officer of Ameren, UE and Ameren Services, in addition to his position
of President, succeeding Charles W. Mueller who retired on December 31, 2003. At
that time, he was also elected  Chairman of CILCORP and CILCO in addition to his
position as President and Chief Executive Officer.


Warner L. Baxter                   43                  Executive Vice President       September 30, 2004
                                                       and Chief Financial
                                                       Officer and Director

From  1983  to  1995,  Mr.  Baxter  was  employed  by  Price   Waterhouse   (now
PricewaterhouseCoopers   LLP).  Mr.  Baxter  joined  UE  in  1995  as  Assistant
Controller.  He was  promoted to  Controller  of UE in 1996 and was elected Vice
President and  Controller of UE and Ameren in 1998.  Mr. Baxter was elected Vice
President and  Controller of CIPS and Genco in 1999 and 2000,  respectively.  He
was  elected  Senior Vice  President - Finance of Ameren,  UE, CIPS and Genco in
2001. In January 2003,  Mr. Baxter was elected  Senior Vice President of CILCORP
and CILCO upon Ameren's  acquisition of those companies.  Mr. Baxter was elected
to Executive Vice  President and Chief  Financial  Officer at Ameren,  UE, CIPS,
Genco, CILCORP and CILCO in October 2003.


                                      -4-

<PAGE>

Martin J. Lyons                    38                  Vice President and             September 30, 2004
                                                       Controller (principal
                                                       accounting officer)

Mr.  Lyons was  appointed  Controller  of Ameren,  UE, CIPS and Genco in October
2001.  He was  elected  Controller  of CILCORP  and CILCO in  January  2003 upon
Ameren's acquisition of those companies. In addition to being Controller, he was
elected to the position of Vice President of Ameren,  UE, CIPS,  Genco,  CILCORP
and CILCO in February 2003. He was previously employed by PricewaterhouseCoopers
LLP for 13 years, most recently as a partner.


Shawn E. Schukar                   43                  Vice President (principal      September 30, 2004
                                                       operating officer)

Shawn Schukar served as Senior Vice President-Utility Operations at IPC prior to
the  Acquisition.  He joined IPC in 1984 as an  engineer at the  Hennepin  Power
Station.  He  has  held  positions  in  power  plant  operations,   power  plant
engineering, generation control, power trading, power marketing, retail pricing,
risk  management,   transmission  operations,  transmission  services,  business
planning, gas control, and customer tariff management. His latest assignment has
been to manage IPC's engineering, purchasing, and field operations.
</TABLE>



ITEM 5.03 Amendments to Articles of  Incorporation  or Bylaws;  Change in Fiscal
Year.

     On  September  30,  2004,   effective  as  of  immediately   prior  to  the
Acquisition,  the  Bylaws of IPC were  amended  by action by  unanimous  written
consent of the Board of  Directors  of IPC to provide that the size of the Board
of  Directors  will be not less than 3 and not more than 8  directors,  with the
number  fixed from time to time within such range by the Board of  Directors  or
the shareholders of IPC.

     Also on September  30,  2004,  effective as of  immediately  following  the
Acquisition,  the following  changes were made to the Bylaws of IPC by action by
unanimous consent of the Board of Directors of IPC:

     o    The annual meeting of shareholders  will be held on the fourth Tuesday
          in April of each year or any other day as  determined by resolution of
          the Board of Directors.  Previously, the annual meeting was to be held
          on such date as fixed by resolution of the Board of Directors.

     o    A director's term automatically expires at the first annual meeting of
          shareholders  following such director's 72nd birthday and the terms of
          any  directors  who are  officers or full time  employees  of IPC will
          automatically   terminate   immediately   upon  their   retirement  or
          termination of employment by IPC.

     o    The  mechanism  for  nominating  persons for  election to the Board of
          Directors or proposing business to be considered by shareholders at an
          annual  meeting  or  special   meeting  was  modified  to  permit  any
          shareholder  who  gives  notice  as  provided  in the  Bylaws of IP to
          nominate persons for election or propose business at such meetings.

For additional  information,  reference is made to the Bylaws of IPC, as amended
September 30, 2004,  which is included as Exhibit 3.1 hereto and incorporated by
reference herein.



SECTION 8 - OTHER EVENTS

Item 8.01 Other Events.

     On September 30, 2004,  Ameren  completed its  acquisition  of IPC and a 20
percent  interest  in EEI from Dynegy and  certain of its  affiliates  for total
consideration of $2.3 billion,  consisting of assumption of existing outstanding
indebtedness of IPC in the amount of $1.823 billion, $100 million in cash placed
into an escrow  account as  described  below,  with the balance  paid in cash on
hand, financed through prior issuances of new shares of Ameren common stock.


                                      -5-

<PAGE>

     Also on September 30, 2004,  Illinova  Corporation,  a subsidiary of Dynegy
and the parent  company and seller of IPC,  Ameren and JPMorgan  Chase Bank,  as
escrow agent,  entered into an escrow agreement providing for Ameren's placement
of $100  million of the cash  portion of the $2.3  billion  purchase  price in a
six-year  escrow  pending   resolution  of  certain   contingent   environmental
obligations  of IPC and  other  Dynegy  affiliates  for  which  Ameren  has been
provided indemnification by Dynegy.

     On October  1,  2004,  IPC filed a notice  with the  Secretary  of State of
Illinois to transact business under the assumed corporate name of AmerenIP.

     For  additional  information,  reference is made to the press release dated
October 1, 2004, which is included as Exhibit 99.1 and incorporated by reference
herein.



SECTION 9 - FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01 Financial Statements and Exhibits.

(c) Exhibits
<TABLE>
<CAPTION>

         <S>                              <C>
      ---------------------------------------------------------------------------------------------------------
      |  3.1                          |   Bylaws of Illinois Power Company as amended September 30, 2004      |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.1                         |   Power Purchase Agreement, by and between Illinois Power Company     |
      |                               |   and Dynegy Power Marketing, Inc., dated as of September 30, 2004.   |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.2                         |   Third Amended Ameren Corporation System Utility Money Pool          |
      |                               |   Agreement, by and among Union Electric Company, Central Illinois    |
      |                               |   Public Service Company, Central Illinois Light Company,             |
      |                               |   AmerenEnergy Resources Generating Company, Illinois Power           |
      |                               |   Company, Ameren Services Company and Ameren Corporation, dated      |
      |                               |   as of September 30, 2004.                                           |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.3                         |   Unilateral Borrowing Agreement, by and among Ameren Corporation,    |
      |                               |   Illinois Power Company and Ameren Services Company, dated as of     |
      |                               |   September 30, 2004.                                                 |
      |-------------------------------|-----------------------------------------------------------------------|
      |  99.1                         |   Press Release, dated October 1, 2004                                |
      ---------------------------------------------------------------------------------------------------------
</TABLE>

     This  combined Form 8-K is being filed  separately  by Ameren  Corporation,
Union Electric Company,  Central Illinois Public Service Company,  Ameren Energy
Generating  Company,  CILCORP Inc.,  Central Illinois Light Company and Illinois
Power Company (each a  "registrant").  Information  contained herein relating to
any individual  registrant has been filed by such  registrant on its own behalf.
No registrant makes any  representation as to information  relating to any other
registrant.


                                      -6-
<PAGE>


                                   SIGNATURES



Pursuant  to the  requirements  of the  Securities  Exchange  Act of 1934,  each
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned  thereunto  duly  authorized.  The  signature  for each  undersigned
company  shall be deemed to relate  only to  matters  having  reference  to such
company or its subsidiaries.

                                  AMEREN CORPORATION
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)


                                  UNION ELECTRIC COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)


                                  CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)


                                  AMEREN ENERGY GENERATING COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)


                                  CILCORP Inc.
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)


                                      -7-
<PAGE>

                                  CENTRAL ILLINOIS LIGHT COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  ILLINOIS POWER COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)





Date:  October 1, 2004


                                      -8-
[{"type": "8-K", "sequence": "1", "filename": "ameren8k10012004.txt", "description": "AMEREN 8K 10-1-2004", "secsgml_size_bytes": 25580}]
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UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM 8-K

                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934

                Date of report (Date of earliest event reported):

                                 September 30, 2004
Commission File Number           Exact Name of Registrant as            IRS Employer
----------------------           Specified in Charter;                  Identification Number
                                 State of Incorporation;                ---------------------
                                 Address and Telephone Number
                                 ----------------------------
1-14756                          Ameren Corporation                     43-1723446
                                 (Missouri Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222

1-2967                           Union Electric Company                 43-0559760
                                 (Missouri Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222

1-3672                           Central Illinois Public Service        37-0211380
                                 Company
                                 (Illinois Corporation)
                                 607 East Adams Street
                                 Springfield, Illinois 62739
                                 (217) 523-3600

333-56594                        Ameren Energy Generating Company       37-1395586
                                 (Illinois Corporation)
                                 1901 Chouteau Avenue
                                 St. Louis, Missouri 63103
                                 (314) 621-3222
2-95569                          CILCORP Inc.                           37-1169387
                                 (Illinois Corporation)
                                 300 Liberty Street
                                 Peoria, Illinois 61602
                                 (309) 677-5230

1-2732                           Central Illinois Light Company         37-0211050
                                 (Illinois Corporation)
                                 300 Liberty Street
                                 Peoria, Illinois 61602
                                 (309) 677-5230

1-3004                           Illinois Power Company                 37-0344645
                                 (Illinois Corporation)
                                 500 South 27th Street
                                 Decatur, Illinois 62521
                                 (217) 424-6600
Check  the  appropriate  box  below  if the  Form  8-K  filing  is  intended  to
simultaneously  satisfy the filing obligation of the registrant under any of the
following provisions:

     [ ] Written  communications  pursuant to Rule 425 under the  Securities Act
(17 CFR 230.425)

     [ ] Soliciting  material pursuant to Rule 14a-12 under the Exchange Act (17
CFR 240.14a-12)

     [ ]  Pre-commencement  communications  pursuant to Rule 14d-2(b)  under the
Exchange Act (17 CFR 240.14d-2(b))

     [ ]  Pre-commencement  communications  pursuant to Rule 13e-4(c)  under the
Exchange Act (17 CFR 240.13e-4(c))

SECTION 1 - REGISTRANT'S BUSINESS AND OPERATIONS

ITEM 1.01 Entry into a Material Definitive Agreement.

     On  September  30,  2004,  the  following   described  material  definitive
agreement was entered into in conjunction with the completion of the Acquisition
(as defined in Item 5.01 below):

     o    A power purchase  agreement between Illinois Power Company ("IPC") and
          Dynegy Power Marketing,  Inc., a subsidiary of Dynegy Inc. ("Dynegy"),
          providing  for the  annual  purchase  by IPC in 2005 and 2006 of 2,800
          megawatts  of firm  capacity.  This  agreement  is  expected to supply
          approximately  70  percent  of IPC's  electric  customer  requirements
          during those two years. The text of the power purchase agreement dated
          as of September 30, 2004 is included as Exhibit 10.1.

SECTION 2 - FINANCIAL INFORMATION

ITEM 2.03 Creation of a Direct  Financial  Obligation or an Obligation  under an
Off-Balance Sheet Arrangement of a Registrant.

     On  September  30,  2004,  in  conjunction   with  the  completion  of  the
Acquisition (as defined in Item 5.01 below), the Ameren  Corporation  ("Ameren")
System  Utility  Money Pool  Agreement  was  amended to add IPC as a party.  The
Utility Money Pool Agreement provides for short-term borrowing arrangements with
and  among  Ameren's  utility  subsidiaries,  Union  Electric  Company,  Central
Illinois Public Service Company,  Central  Illinois Light Company,  AmerenEnergy
Resources  Generating  Company  (as a lender  only)  and IPC,  Ameren's  service
company subsidiary,  Ameren Services Company, and Ameren (as a lender only). The
text of the Third Amended Ameren Corporation System Utility Money Pool Agreement
dated as of September 30, 2004 is included as Exhibit 10.2.

                                      -2-
Also on September  30, 2004, a unilateral  borrowing  agreement was entered
into between Ameren,  IPC and Ameren Services  Company which enables IPC to make
short-term borrowings directly from Ameren up to an aggregate amount outstanding
at any  time of  $500  million.  Ameren  Services  Company  is  responsible  for
operation  and  administration  of the  agreement.  The  text of the  unilateral
borrowing agreement dated as of September 30, 2004 is included as Exhibit 10.3.

ITEM 2.04  Triggering  Events That  Accelerate  or  Increase a Direct  Financial
Obligation or an Obligation under an Off-Balance Sheet Arrangement.

     The  completion  of  the  Acquisition  (as  defined  in  Item  5.01  below)
constitutes  a Change of  Control  of IPC,  as  defined  in the  indenture  (the
"Indenture")  governing the 11 1/2% Mortgage Bonds due 2010 of IPC (the "11 1/2%
Bonds"). In accordance with the Indenture,  IPC is required to commence,  within
30 days  following  the  Change  of  Control,  a tender  offer to  purchase  all
outstanding  11 1/2% Bonds at a price of 101% of their  principal  amount,  plus
accrued  and unpaid  interest to the date of  purchase.  IPC intends to commence
such an offer on or before October 30, 2004.

     As a  result  of  certain  actions  taken by IPC  immediately  prior to the
completion of the Acquisition (as defined in Item 5.01 below),  IPC has notified
the  trustee  under the  Indenture  that a  Triggering  Event (as defined in the
Indenture)  has occurred with respect to the 11 1/2% Bonds.  A Triggering  Event
enables the holders of at least 25% of the  outstanding 11 1/2% Bonds to deliver
a notice to IPC requiring IPC to redeem the 11 1/2% Bonds at a redemption  price
specified in the Indenture.

SECTION 5 - CORPORATE GOVERNANCE AND MANAGEMENT

ITEM 5.01 Changes in Control of Registrant.

     On September 30, 2004,  Ameren  completed its  acquisition of IPC and a 20%
interest  in  Electric  Energy,  Inc.  ("EEI")  from  Dynegy and  certain of its
affiliates (the "Acquisition").  As a result of the Acquisition, Ameren obtained
all of the outstanding common stock, without par value, and approximately 73% of
the  total  outstanding  preferred  stock,  $50 par  value,  of IPC.  The  total
consideration  for Ameren's  acquisition of IPC and the 20% interest in EEI from
Dynegy and certain of its affiliates  was $2.3 billion  consisting of assumption
of existing IPC outstanding  indebtedness in the amount of $1.823 billion,  $100
million in cash placed into an escrow  account as  described in Item 8.01 below,
with the balance paid with cash on hand financed  through prior issuances of new
shares of Ameren common stock.

     In connection with the Acquisition,  and as more fully described in Section
5.02 below,  (i) effective as of immediately  prior to the closing,  the size of
the Board of  Directors of IPC was  increased  from 3 to 6 and Warner L. Baxter,
Gary L.  Rainwater  and  Steven R.  Sullivan  were  elected  to fill the 3 newly
created  vacancies,  (ii) effective as of the closing,  R. Blake Young, Carol F.
Graebner and Bruce A.  Williamson  resigned as members of the Board of Directors
of IPC and (iii)  effective as of immediately  following the closing,  Daniel F.
Cole,  Thomas R. Voss and David A.  Whiteley  were  elected  to fill the 3 newly
created vacancies.

ITEM 5.02 Departure of Directors or Principal  Officers;  Election of Directors;
Appointment of Principal Officers.

     On  September  30,  2004,  in  connection   with  the  Acquisition  and  in
conjunction  with an amendment  to the Bylaws of IPC as more fully  described in
Item 5.03 below,  effective as of immediately prior to the closing,  the size of
the  Board  of  Directors  of IPC was  increased  from 3 to 6 and the  following
persons, each of whom are employed by Ameren or its affiliates, were selected to
fill the 3  vacancies:  Warner  L.  Baxter,  Gary L.  Rainwater  and  Steven  R.
Sullivan.  Additionally,  on the same date and effective as of the closing,  the
following  members of the Board of  Directors of IPC  resigned:  R. Blake Young,
Carol F.  Graebner  and  Bruce A.  Willamson.  Following  the  resignations  and
effective  immediately  following the closing,  on the same date,  the following
persons, each of whom are employed by Ameren or its affiliates, were selected to
fill the 3 vacancies: Daniel F. Cole, Thomas R. Voss and David A. Whiteley.

                                      -3-
In addition,  in furtherance of the Acquisition,  the following  officers of IPC
resigned as of the closing:

         Name                         Title

R. Blake Young         President
                       (principal executive officer and
                       principal operating officer)

Nicholas J. Caruso     Executive Vice President and
                       Chief Financial Officer

Peggy E. Carter        Managing Director and Controller
                       (principal accounting officer)

Mr. Shawn E. Schukar,  a Senior Vice President at IPC prior to the  Acquisition,
was appointed  Vice  President and will be the senior  operating  officer of IPC
following the Acquisition.

The  following  officers,  all  employees  of Ameren or its  subsidiaries,  were
appointed as officers of IPC as of  immediately  following  the  Acquisition  to
serve indefinitely:
Date First Elected or
                                                                                      ---------------------
                                                       Present Position at IPC        Appointed to Present
                                                       -----------------------        --------------------
        Name              Age at October 1, 2004       and Business Experience             Position
        ----              -----------------------      -----------------------             --------
Gary L. Rainwater                  58                  Chairman, President and        September 30, 2004
                                                       Director

Mr.  Rainwater began his career with Union Electric Company ("UE") in 1979 as an
engineer.  He was  elected  Vice  President -  Corporate  Planning in 1993.  Mr.
Rainwater  was elected  Executive  Vice  President  of Central  Illinois  Public
Service  Company  ("CIPS")  in  January  1997 and was named to his  position  as
President and Chief  Executive  Officer of CIPS in December 1997. He was elected
President of Ameren Energy Resources Company  ("Resources  Company") in 1999 and
Ameren Energy Generating Company ("Genco") in 2000. He was elected President and
Chief  Operating  Officer of Ameren,  UE and Ameren  Services  Company  ("Ameren
Services")  in  August  2001 at  which  time he  relinquished  his  position  as
President of Resources  Company and Genco.  In January 2003,  Mr.  Rainwater was
named  President and Chief  Executive  Officer of CILCORP Inc.  ("CILCORP")  and
Central  Illinois  Light Company  ("CILCO")  upon Ameren's  acquisition of those
companies.  Effective  January 1, 2004, Mr.  Rainwater became Chairman and Chief
Executive Officer of Ameren, UE and Ameren Services, in addition to his position
of President, succeeding Charles W. Mueller who retired on December 31, 2003. At
that time, he was also elected  Chairman of CILCORP and CILCO in addition to his
position as President and Chief Executive Officer.

Warner L. Baxter                   43                  Executive Vice President       September 30, 2004
                                                       and Chief Financial
                                                       Officer and Director

From  1983  to  1995,  Mr.  Baxter  was  employed  by  Price   Waterhouse   (now
PricewaterhouseCoopers   LLP).  Mr.  Baxter  joined  UE  in  1995  as  Assistant
Controller.  He was  promoted to  Controller  of UE in 1996 and was elected Vice
President and  Controller of UE and Ameren in 1998.  Mr. Baxter was elected Vice
President and  Controller of CIPS and Genco in 1999 and 2000,  respectively.  He
was  elected  Senior Vice  President - Finance of Ameren,  UE, CIPS and Genco in
2001. In January 2003,  Mr. Baxter was elected  Senior Vice President of CILCORP
and CILCO upon Ameren's  acquisition of those companies.  Mr. Baxter was elected
to Executive Vice  President and Chief  Financial  Officer at Ameren,  UE, CIPS,
Genco, CILCORP and CILCO in October 2003.

                                      -4-
Martin J. Lyons                    38                  Vice President and             September 30, 2004
                                                       Controller (principal
                                                       accounting officer)

Mr.  Lyons was  appointed  Controller  of Ameren,  UE, CIPS and Genco in October
2001.  He was  elected  Controller  of CILCORP  and CILCO in  January  2003 upon
Ameren's acquisition of those companies. In addition to being Controller, he was
elected to the position of Vice President of Ameren,  UE, CIPS,  Genco,  CILCORP
and CILCO in February 2003. He was previously employed by PricewaterhouseCoopers
LLP for 13 years, most recently as a partner.

Shawn E. Schukar                   43                  Vice President (principal      September 30, 2004
                                                       operating officer)

Shawn Schukar served as Senior Vice President-Utility Operations at IPC prior to
the  Acquisition.  He joined IPC in 1984 as an  engineer at the  Hennepin  Power
Station.  He  has  held  positions  in  power  plant  operations,   power  plant
engineering, generation control, power trading, power marketing, retail pricing,
risk  management,   transmission  operations,  transmission  services,  business
planning, gas control, and customer tariff management. His latest assignment has
been to manage IPC's engineering, purchasing, and field operations.
ITEM 5.03 Amendments to Articles of  Incorporation  or Bylaws;  Change in Fiscal
Year.

     On  September  30,  2004,   effective  as  of  immediately   prior  to  the
Acquisition,  the  Bylaws of IPC were  amended  by action by  unanimous  written
consent of the Board of  Directors  of IPC to provide that the size of the Board
of  Directors  will be not less than 3 and not more than 8  directors,  with the
number  fixed from time to time within such range by the Board of  Directors  or
the shareholders of IPC.

     Also on September  30,  2004,  effective as of  immediately  following  the
Acquisition,  the following  changes were made to the Bylaws of IPC by action by
unanimous consent of the Board of Directors of IPC:

     o    The annual meeting of shareholders  will be held on the fourth Tuesday
          in April of each year or any other day as  determined by resolution of
          the Board of Directors.  Previously, the annual meeting was to be held
          on such date as fixed by resolution of the Board of Directors.

     o    A director's term automatically expires at the first annual meeting of
          shareholders  following such director's 72nd birthday and the terms of
          any  directors  who are  officers or full time  employees  of IPC will
          automatically   terminate   immediately   upon  their   retirement  or
          termination of employment by IPC.

     o    The  mechanism  for  nominating  persons for  election to the Board of
          Directors or proposing business to be considered by shareholders at an
          annual  meeting  or  special   meeting  was  modified  to  permit  any
          shareholder  who  gives  notice  as  provided  in the  Bylaws of IP to
          nominate persons for election or propose business at such meetings.

For additional  information,  reference is made to the Bylaws of IPC, as amended
September 30, 2004,  which is included as Exhibit 3.1 hereto and incorporated by
reference herein.

SECTION 8 - OTHER EVENTS

Item 8.01 Other Events.

     On September 30, 2004,  Ameren  completed its  acquisition  of IPC and a 20
percent  interest  in EEI from Dynegy and  certain of its  affiliates  for total
consideration of $2.3 billion,  consisting of assumption of existing outstanding
indebtedness of IPC in the amount of $1.823 billion, $100 million in cash placed
into an escrow  account as  described  below,  with the balance  paid in cash on
hand, financed through prior issuances of new shares of Ameren common stock.

                                      -5-
Also on September 30, 2004,  Illinova  Corporation,  a subsidiary of Dynegy
and the parent  company and seller of IPC,  Ameren and JPMorgan  Chase Bank,  as
escrow agent,  entered into an escrow agreement providing for Ameren's placement
of $100  million of the cash  portion of the $2.3  billion  purchase  price in a
six-year  escrow  pending   resolution  of  certain   contingent   environmental
obligations  of IPC and  other  Dynegy  affiliates  for  which  Ameren  has been
provided indemnification by Dynegy.

     On October  1,  2004,  IPC filed a notice  with the  Secretary  of State of
Illinois to transact business under the assumed corporate name of AmerenIP.

     For  additional  information,  reference is made to the press release dated
October 1, 2004, which is included as Exhibit 99.1 and incorporated by reference
herein.

SECTION 9 - FINANCIAL STATEMENTS AND EXHIBITS

Item 9.01 Financial Statements and Exhibits.

(c) Exhibits
---------------------------------------------------------------------------------------------------------
      |  3.1                          |   Bylaws of Illinois Power Company as amended September 30, 2004      |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.1                         |   Power Purchase Agreement, by and between Illinois Power Company     |
      |                               |   and Dynegy Power Marketing, Inc., dated as of September 30, 2004.   |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.2                         |   Third Amended Ameren Corporation System Utility Money Pool          |
      |                               |   Agreement, by and among Union Electric Company, Central Illinois    |
      |                               |   Public Service Company, Central Illinois Light Company,             |
      |                               |   AmerenEnergy Resources Generating Company, Illinois Power           |
      |                               |   Company, Ameren Services Company and Ameren Corporation, dated      |
      |                               |   as of September 30, 2004.                                           |
      |-------------------------------|-----------------------------------------------------------------------|
      |  10.3                         |   Unilateral Borrowing Agreement, by and among Ameren Corporation,    |
      |                               |   Illinois Power Company and Ameren Services Company, dated as of     |
      |                               |   September 30, 2004.                                                 |
      |-------------------------------|-----------------------------------------------------------------------|
      |  99.1                         |   Press Release, dated October 1, 2004                                |
      ---------------------------------------------------------------------------------------------------------
This  combined Form 8-K is being filed  separately  by Ameren  Corporation,
Union Electric Company,  Central Illinois Public Service Company,  Ameren Energy
Generating  Company,  CILCORP Inc.,  Central Illinois Light Company and Illinois
Power Company (each a  "registrant").  Information  contained herein relating to
any individual  registrant has been filed by such  registrant on its own behalf.
No registrant makes any  representation as to information  relating to any other
registrant.

                                      -6-
SIGNATURES

Pursuant  to the  requirements  of the  Securities  Exchange  Act of 1934,  each
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned  thereunto  duly  authorized.  The  signature  for each  undersigned
company  shall be deemed to relate  only to  matters  having  reference  to such
company or its subsidiaries.

                                  AMEREN CORPORATION
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  UNION ELECTRIC COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  CENTRAL ILLINOIS PUBLIC SERVICE COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  AMEREN ENERGY GENERATING COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  CILCORP Inc.
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                      -7-
CENTRAL ILLINOIS LIGHT COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

                                  ILLINOIS POWER COMPANY
                                  (Registrant)

                                  /s/ Martin J. Lyons
                                  ---------------------------------------
                                  Martin J. Lyons
                                  Vice President and Controller
                                  (Principal Accounting Officer)

Date:  October 1, 2004

                                      -8-