SCHEDULE 14A
                    Proxy Statement Pursuant to Section 14(a)
            of the Securities Exchange Act of 1934 (Amendment No. __)


Filed by the Registrant    [  ]

Filed by a Party other than the Registrant    [X]

Check the appropriate box:

[ ]     Preliminary Proxy Statement
[ ]     Confidential, for Use of the Commission Only (as permitted by
        Rule 14a-6(e)(2))
[ ]     Definitive Proxy Statement
[X]     Definitive Additional Materials
[ ]     Soliciting Material Pursuant to ss. 240.14a-12

                                 CSX CORPORATION

                (Name of Registrant as Specified In Its Charter)
               THE CHILDREN'S INVESTMENT FUND MANAGEMENT (UK) LLP
             THE CHILDREN'S INVESTMENT FUND MANAGEMENT (CAYMAN) LTD.
                      THE CHILDREN'S INVESTMENT MASTER FUND
                            3G CAPITAL PARTNERS LTD.
                            3G CAPITAL PARTNERS, L.P.
                                  3G FUND L.P.
                                CHRISTOPHER HOHN
                                ALEXANDRE BEHRING
                               GILBERT H. LAMPHERE
                               TIMOTHY T. O'TOOLE
                                 GARY L. WILSON
    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee
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[ ]     Check box if any part of the fee is offset as provided by Exchange Act
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On February 7, 2008, The Children's Investment Fund Management (UK) LLP sent a
letter to the Board of Directors of CSX Corp., a copy of which if filed herewith
as Exhibit 1.