**UNITED      STATES**

**SECURITIES      AND EXCHANGE COMMISSION**

**FORM      10-Q/A**

**Amendment      No. 1**

**                      for the Quarterly Period Ended September 30, 2005**

|  CommissionFile                Number | Exact                Name of Registrant as Specified in its Charter;State                of Incorporation;Address                and Telephone Number |  IRS                EmployerIdentification                No. |
|--------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------|
|                                       |                                                                                                                                                  |                                                               |
| 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                                                                                                                         |                                                               |
|                                       |                                                                                                                                                  |                                                               |
| 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)                677-5271                                                                                                                         |                                                               |
|                                       |                                                                                                                                                  |                                                               |
| 1-2732                                     | **Central                Illinois Light Company**                                                                                                     | 37-0211050                                                         |
|                                       | (Illinois                Corporation)                                                                                                                 |                                                               |
|                                       | 300                Liberty Street                                                                                                                     |                                                               |
|                                       | Peoria,                Illinois 61602                                                                                                                 |                                                               |
|                                       | (309)                677-5271                                                                                                                         |                                                               |
|                                       |                                                                                                                                                  |                                                               |

----

| Ameren                Corporation               | Yes | (X)                            | No | (                  ) |
|-------------------------------------------------|-----|--------------------------------|----|--------------------------------|
| Union                Electric Company           | Yes | (                  ) | No | (X)                            |
| Ameren                Energy Generating Company | Yes | (                  ) | No | (X)                            |
| CILCORP                Inc.                     | Yes | (                  ) | No | (X)                            |
| Central                Illinois Light Company   | Yes | (                  ) | No | (X)                            |

| Ameren                Corporation               | Yes | (                  ) | No | (X) |
|-------------------------------------------------|-----|--------------------------------|----|-----|
| Union                Electric Company           | Yes | (                  ) | No | (X) |
| Ameren                Energy Generating Company | Yes | (                  ) | No | (X) |
| CILCORP                Inc.                     | Yes | (                  ) | No | (X) |
| Central                Illinois Light Company   | Yes | (                  ) | No | (X) |

| Ameren                Corporation               | Common                stock, $.01 par value per share - 204,273,646                                                                                                                                                     |
|-------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                            |                                                                                                                                                                                                                    |
| Union                Electric Company           | Common                stock, $5 par value per share, held by AmerenCorporation                (parent company of the Registrant) - 102,123,834                                                                          |
|                                            |                                                                                                                                                                                                                    |
| Ameren                Energy Generating Company | Common                stock, no par value, held by Ameren EnergyDevelopment                Company (parent company of theRegistrant                and indirect subsidiary of AmerenCorporation)                - 2,000 |
|                                            |                                                                                                                                                                                                                    |
| CILCORP                Inc.                     | Common                stock, no par value, held by AmerenCorporation                (parent company of the Registrant) - 1,000                                                                                          |
|                                            |                                                                                                                                                                                                                    |
| Central                Illinois Light Company   | Common                stock, no par value, held by CILCORP Inc. (parent                company of the Registrant and subsidiary ofAmeren                Corporation) - 13,563,871                                       |

----

**EXPLANATORY      NOTE**

----

**ITEM      6.   **
**EXHIBITS**
**.      **

| **Exhibit                Designation**                       | **Registrant(s)** | **Nature                of Exhibit**                                                                                                                                         |
|--------------------------------------------------------------|-------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                         |
| **Letter                Re Change in Accounting Principles** |
| 18.1                                                         | Ameren            | Letter                from PricewaterhouseCoopers LLP, dated February 7, 2007, regarding                change                in                accounting principles        |
| 18.2                                                         | UE                | Letter                from PricewaterhouseCoopers LLP, dated February 7, 2007, regarding                change                in                accounting principles        |
| 18.3                                                         | Genco             | Letter                from PricewaterhouseCoopers LLP, dated February 7, 2007, regarding                change                in                accounting principles        |
| 18.4                                                         | CILCORP           | Letter                from PricewaterhouseCoopers LLP, dated February 7, 2007, regarding                change                in                accounting principles        |
| 18.5                                                         | CILCO             | Letter                from PricewaterhouseCoopers LLP, dated February 7, 2007, regarding                changein                accounting principles                        |
| **Rule                13a-14(a) / 15d-14(a) Certifications** |
| 31.1                                                         | Ameren            | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                Ameren*                                                |
| 31.2                                                         | Ameren            | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                Ameren*                                                |
| 31.3                                                         | UE                | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                UE*                                                    |
| 31.4                                                         | UE                | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                UE*                                                    |
| 31.5                                                         | CIPS              | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                CIPS*                                                  |
| 31.6                                                         | CIPS              | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                CIPS*                                                  |
| 31.7                                                         | Genco             | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                Genco*                                                 |
| 31.8                                                         | Genco             | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                Genco*                                                 |
| 31.9                                                         | CILCORP           | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                CILCORP*                                               |
| 31.10                                                        | CILCORP           | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                CILCORP*                                               |
| 31.11                                                        | CILCO             | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                CILCO*                                                 |
| 31.12                                                        | CILCO             | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                CILCO*                                                 |
| 31.13                                                        | IP                | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                IP*                                                    |
| 31.14                                                        | IP                | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                IP*                                                    |
| 31.15                                                        | Ameren            | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of Ameren                with respect                to the Form 10-Q/A  |
| 31.16                                                        | Ameren            | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of Ameren                with respect                to the Form 10-Q/A  |
| 31.17                                                        | UE                | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of UE                with respect                to the Form 10-Q/A      |
| 31.18                                                        | UE                | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of UE                with respect                to the Form 10-Q/A      |
| 31.19                                                        | Genco             | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of Genco                with respect                to the Form 10-Q/A   |
| 31.20                                                        | Genco             | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of Genco                with respect                to the Form 10-Q/A   |
| 31.21                                                        | CILCORP           | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of                CILCORP with respect                to the Form 10-Q/A |
| 31.22                                                        | CILCORP           | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of                CILCORP with respect                to the Form 10-Q/A |
| 31.23                                                        | CILCO             | Rule                13a-14(a)/15d-14(a) Certification of Principal Executive Officer                of CILCO                with respect                to the Form 10-Q/A   |
| 31.24                                                        | CILCO             | Rule                13a-14(a)/15d-14(a) Certification of Principal Financial Officer                of CILCO                with respect                to the Form 10-Q/A   |
|                                                         |              |                                                                                                                                                                         |
| **Section                1350 Certifications**               |
| 32.1                                                         | Ameren            | Section                1350 Certification of Principal Executive Officer of                Ameren*                                                                           |
| 32.2                                                         | Ameren            | Section                1350 Certification of Principal Financial Officer of                Ameren*                                                                           |
| 32.3                                                         | UE                | Section                1350 Certification of Principal Executive Officer of                UE*                                                                               |

----

| 32.4  | UE      | Section                1350 Certification of Principal Financial Officer of                UE*      |
|-------|---------|-----------------------------------------------------------------------------------------------------|
| 32.5  | CIPS    | Section                1350 Certification of Principal Executive Officer of                CIPS*    |
| 32.6  | CIPS    | Section                1350 Certification of Principal Financial Officer of                CIPS*    |
| 32.7  | Genco   | Section                1350 Certification of Principal Executive Officer of                Genco*   |
| 32.8  | Genco   | Section                1350 Certification of Principal Financial Officer of                Genco*   |
| 32.9  | CILCORP | Section                1350 Certification of Principal Executive Officer of                CILCORP* |
| 32.10 | CILCORP | Section                1350 Certification of Principal Financial Officer of                CILCORP* |
| 32.11 | CILCO   | Section                1350 Certification of Principal Executive Officer of                CILCO*   |
| 32.12 | CILCO   | Section                1350 Certification of Principal Financial Officer of                CILCO*   |
| 32.13 | IP      | Section                1350 Certification of Principal Executive Officer of                IP*      |
| 32.14 | IP      | Section                1350 Certification of Principal Financial Officer of                IP*      |

----

**SIGNATURES**

*                          *
** **

* *

* *

* *

* *