EXHIBIT 32

                        GATX CORPORATION AND SUBSIDIARIES

                CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350

    CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

      In connection with the Quarterly Report of GATX Corporation (the
"Company") on Form 10-Q for the period ending June 30, 2007, as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), each of
the undersigned officers of the Company, certify, pursuant to 18 U.S.C. Section
1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002,
that:

            (1) The Report fully complies with the requirements of section 13(a)
      or 15(d) of the Securities Exchange Act of 1934; and

            (2) The information contained in the Report fairly presents, in all
      material respects, the financial condition and results of operations of
      the Company.

       /s/ Brian A. Kenney                              /s/ Robert C. Lyons
------------------------------------  ------------------------------------------
        Brian A. Kenney                                   Robert C. Lyons
    Chairman, President and                          Senior Vice President and
    Chief Executive Officer                            Chief Financial Officer

July 31, 2007

      This certification accompanies the Report pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002 and shall not be deemed filed by GATX Corporation for
purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

      A signed original of this written statement required by Section 906 has
been provided to GATX Corporation and will be retained by GATX Corporation and
furnished to the Securities and Exchange Commission or its staff upon request.