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

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

                                  SCHEDULE 13D

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934
                               (AMENDMENT NO. 2)*

                              TransAlta Corporation
 ------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
 ------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    89346D107
 ------------------------------------------------------------------------------
                                 (CUSIP Number)

                              Mr. Christopher Hohn
                            The Children's Investment
                            Fund Management (UK) LLP
                                7 Clifford Street
                                 London W1S 2WE
                                 United Kingdom
                                +44 20 7440 2330

                                 With a copy to:

                              Marc Weingarten, Esq.
                            Schulte Roth & Zabel LLP
                                919 Third Avenue
                            New York, New York 10022
                                 (212) 756-2000

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                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                         (Continued on following pages)

                                January 13, 2009
 ------------------------------------------------------------------------------
             (Date of Event which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following
box. [ ]

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
to whom copies are to be sent.

--------------------------
* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page. The information required on the
remainder of this cover page shall not be deemed to be "filed" for the purpose
of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise
subject to the liabilities of that section of the Act but shall be subject to
all other provisions of the Act (however, see the Notes).

                               (Page 1 of 8 Pages)







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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 2 OF 8  Pages
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--------------------------------------------------------------------------------
    1       NAME OF REPORTING PERSON
            I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
            The Children's Investment Fund Management (UK) LLP
-----------------------------------------------------------------------------
    2       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*       (a) [ ]
                                                                    (b) [ ]
-----------------------------------------------------------------------------
    3       SEC USE ONLY

-----------------------------------------------------------------------------
    4       SOURCE OF FUNDS*

            AF
-----------------------------------------------------------------------------
    5       CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
            ITEMS 2(d) or 2(e)                                         [X]

-----------------------------------------------------------------------------
    6       CITIZENSHIP OR PLACE OF ORGANIZATION

            England
-----------------------------------------------------------------------------
    7       SOLE VOTING POWER

                                  -0-
-----------------------------------------------------------------------------
 NUMBER OF                 8      SHARED VOTING POWER
  SHARES
BENEFICIALLY                      11,491,909
  OWNED BY            -------------------------------------------------------
    EACH                   9      SOLE DISPOSITIVE POWER
 REPORTING
PERSON WITH                       -0-
                      -------------------------------------------------------
                           10     SHARED DISPOSITIVE POWER

                                  11,491,909
-----------------------------------------------------------------------------
    11      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            5.8%
-----------------------------------------------------------------------------
    12      CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
            CERTAIN SHARES*
                                                                        [ ]
-----------------------------------------------------------------------------
    13      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

            5.8%
-----------------------------------------------------------------------------
    14      TYPE OF REPORTING PERSON*

            PN
-----------------------------------------------------------------------------







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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 3  OF 8  Pages
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--------------------------------------------------------------------------------
    1       NAME OF REPORTING PERSON
            I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
            The Children's Investment Fund Management (Cayman) Ltd.
-----------------------------------------------------------------------------
    2       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*       (a) [ ]
                                                                    (b) [ ]
-----------------------------------------------------------------------------
    3       SEC USE ONLY

-----------------------------------------------------------------------------
    4       SOURCE OF FUNDS*

            AF
-----------------------------------------------------------------------------
    5       CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
            ITEMS 2(d) or 2(e)                                         [X]

-----------------------------------------------------------------------------
    6       CITIZENSHIP OR PLACE OF ORGANIZATION

            Cayman Islands
-----------------------------------------------------------------------------
    7       SOLE VOTING POWER

                                  -0-
-----------------------------------------------------------------------------
NUMBER OF                 8      SHARED VOTING POWER
  SHARES
BENEFICIALLY                      11,491,909
  OWNED BY            -------------------------------------------------------
    EACH                   9      SOLE DISPOSITIVE POWER
 REPORTING
PERSON WITH                       -0-
                      -------------------------------------------------------
                           10     SHARED DISPOSITIVE POWER

                                  11,491,909
-----------------------------------------------------------------------------
    11      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            5.8%
-----------------------------------------------------------------------------
    12      CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
            CERTAIN SHARES*
                                                                        [ ]
-----------------------------------------------------------------------------
    13      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

            5.8%
-----------------------------------------------------------------------------
    14      TYPE OF REPORTING PERSON*

            CO
-----------------------------------------------------------------------------







--------------------------------------------------------------------------------
CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 4 OF 8  Pages
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--------------------------------------------------------------------------------
    1       NAME OF REPORTING PERSON
            I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
            The Children's Investment Master Fund
-----------------------------------------------------------------------------
    2       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*       (a) [ ]
                                                                    (b) [ ]

-----------------------------------------------------------------------------
    3       SEC USE ONLY

-----------------------------------------------------------------------------
    4       SOURCE OF FUNDS*

            WC
-----------------------------------------------------------------------------
    5       CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
            ITEMS 2(d) or 2(e)                                         [X]

-----------------------------------------------------------------------------
    6       CITIZENSHIP OR PLACE OF ORGANIZATION

            Cayman Islands
-----------------------------------------------------------------------------
    7       SOLE VOTING POWER

                                  -0-
-----------------------------------------------------------------------------
NUMBER OF                 8      SHARED VOTING POWER
  SHARES
BENEFICIALLY                      11,491,909
  OWNED BY            -------------------------------------------------------
    EACH                   9      SOLE DISPOSITIVE POWER
 REPORTING
PERSON WITH                       -0-
                      -------------------------------------------------------
                           10     SHARED DISPOSITIVE POWER

                                  11,491,909
-----------------------------------------------------------------------------
    11      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            5.8%
-----------------------------------------------------------------------------
    12      CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
            CERTAIN SHARES*
                                                                        [ ]
-----------------------------------------------------------------------------
    13      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

            5.8%
-----------------------------------------------------------------------------
    14      TYPE OF REPORTING PERSON*

            CO
-----------------------------------------------------------------------------






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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 5 OF 8   Pages
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
    1       NAME OF REPORTING PERSON
            I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
            Christopher Hohn
-----------------------------------------------------------------------------
    2       CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*       (a) [ ]
                                                                    (b) [ ]

-----------------------------------------------------------------------------
    3       SEC USE ONLY

-----------------------------------------------------------------------------
    4       SOURCE OF FUNDS*

            AF
-----------------------------------------------------------------------------
    5       CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
            ITEMS 2(d) or 2(e)                                         [X]

-----------------------------------------------------------------------------
    6       CITIZENSHIP OR PLACE OF ORGANIZATION

            United Kingdom
-----------------------------------------------------------------------------
    7      SOLE VOTING POWER

                                  -0-
-----------------------------------------------------------------------------
NUMBER OF                 8      SHARED VOTING POWER
  SHARES
BENEFICIALLY                      11,491,909
  OWNED BY            -------------------------------------------------------
    EACH                   9      SOLE DISPOSITIVE POWER
 REPORTING
PERSON WITH                       -0-
                      -------------------------------------------------------
                           10     SHARED DISPOSITIVE POWER

                                  11,491,909
-----------------------------------------------------------------------------
    11      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            5.8%
-----------------------------------------------------------------------------
    12      CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
            CERTAIN SHARES*
                                                                        [ ]
-----------------------------------------------------------------------------
    13      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

            5.8%
-----------------------------------------------------------------------------
    14      TYPE OF REPORTING PERSON*

            IN
-----------------------------------------------------------------------------









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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE  6 OF 8  Pages
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The Schedule 13D filed on August 15, 2008 (the  "Schedule  13D"),  as amended by
the  Amendment No. 1 filed on September  10, 2008 by The  Children's  Investment
Fund  Management  (UK)  LLP,  an  English  limited  liability  partnership,  The
Children's  Investment Fund Management  (Cayman) Ltd., a Cayman Islands exempted
company,  The  Children's  Investment  Master  Fund, a Cayman  Islands  exempted
company,  and Christopher Hohn (together,  the "Reporting  Persons") relating to
the shares  ("Shares") of common stock of TransAlta  Corporation (the "Issuer"),
is hereby  amended as set forth below by this  Amendment  No. 2 to the  Schedule
13D.

ITEM 5.           INTEREST IN SECURITIES OF THE ISSUER

Paragraphs  (a),  (b), and (c) of Item 5 of the Schedule 13D are hereby  amended
and restated as follows:

       (a) As of the close of  business  on  January  14,  2009,  the  Reporting
Persons  beneficially  owned an aggregate  of  11,491,909  Shares,  constituting
approximately 5.8% of the Shares outstanding.

       The aggregate  percentage of Shares  beneficially  owned by the Reporting
Persons is based upon 197,600,000 Shares outstanding,  which is the total number
of Shares  issued and  outstanding  as of September  30, 2008 as reported in the
Issuer's Form 6-K filed on October 31, 2008.

       (b) Each of the  Reporting  Persons  share  power to vote and  direct the
disposition of the Shares held by the TCI Fund.

            (c) Information concerning transactions in the Shares effected by
the Reporting Persons during the past sixty days is set forth in Appendix A
hereto and is incorporated herein by reference.







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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 7  OF 8 Pages
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                                   SIGNATURES

       After  reasonable  inquiry and to the best of my knowledge and belief,  I
certify that the information  set forth in this statement is true,  complete and
correct.

Dated:  January 16, 2009


                                            THE CHILDREN'S INVESTMENT FUND
                                            MANAGEMENT (UK) LLP


                                            /s/ Christopher Hohn
                                            ------------------------------
                                            Christopher Hohn
                                            Managing Partner



                                            THE CHILDREN'S INVESTMENT FUND
                                            MANAGEMENT (CAYMAN) LTD.


                                            /s/ David DeRosa
                                            ------------------------------
                                            David DeRosa
                                            Director



                                            THE CHILDREN'S INVESTMENT
                                            MASTER FUND


                                            /s/ David DeRosa
                                            ------------------------------
                                            David DeRosa
                                            Director


                                            /s Christopher Hohn
                                            ------------------------------
                                            Christopher Hohn









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CUSIP NO.      89346D107            SCHEDULE 13D/A           PAGE 8  OF 8 Pages
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                                   APPENDIX A

                   TRANSACTIONS IN THE SHARES EFFECTED BY THE
             REPORTING PERSONS SINCE THE FILING OF THE SCHEDULE 13D
           (UNLESS OTHERWISE STATED, ALL TRANSACTIONS WERE EFFECTED IN
                                THE OPEN MARKET)


        The Children's Investment Master Fund


          Date of Trade    Shares Purchased (Sold)        Price per Share(1)
            09-Sep-08                   163,900                    31.591
            10-Sep-08                   182,500                    31.824
            17-Sep-08                    33,400                    27.659
            18-Sep-08                       200                    28.954
            30-Sep-08                    24,300                    26.364
            06-Oct-08                    17,800                    23.107
            09-Oct-08                   115,373                    25.448
            09-Oct-08                   250,000                    19.675
            10-Oct-08                   150,000                    17.756
            06-Nov-08                 (154,600)                    19.074
            07-Nov-08                  (37,700)                    20.205
            10-Nov-08                  (35,200)                    19.791
            11-Nov-08                 (165,500)                    19.090
            12-Nov-08                 (138,000)                    18.335
            13-Nov-08                  (40,200)                    18.462
            02-Dec-08                  (44,700)                    17.740
            03-Dec-08                  (14,800)                    16.926
            04-Dec-08                  (24,300)                    17.305
            08-Dec-08                  (83,300)                    17.402
            09-Dec-08                  (65,900)                    17.162
            10-Dec-08                  (55,100)                    17.373
            11-Dec-08                  (86,264)                    18.042
            12-Dec-08                  (40,700)                    17.519
            15-Dec-08                  (26,100)                    17.485
            15-Dec-08                 (500,000)                    17.548
            16-Dec-08                  (47,000)                    18.328
            18-Dec-08                 (112,900)                    18.688
            18-Dec-08                 (600,000)                    18.528
            19-Dec-08                  (92,300)                    18.341
            22-Dec-08                  (55,600)                    18.460
            23-Dec-08                  (61,500)                    18.293
            29-Dec-08                  (51,300)                    18.910
            07-Jan-09                  (18,000)                    20.726
            08-Jan-09                  (15,400)                    20.732
            09-Jan-09                  (17,400)                    20.294
            12-Jan-09                 (118,100)                    19.317
            13-Jan-09                  (46,400)                    18.878
            13-Jan-09                 (800,000)                    18.983
            14-Jan-09                  (14,700)                    22.888



----------------------
(1) US dollar amounts calculated using exchange rates in effect on the date of
trade.