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                                                                     EXHIBIT 10A

                                GATX CORPORATION
                     2004 EQUITY INCENTIVE COMPENSATION PLAN
                           PERFORMANCE SHARE AGREEMENT

      THIS AGREEMENT, entered into as of January 1, 2005, by and between the
Participant and GATX Corporation (the "Company");

      WHEREAS, the Company maintains the GATX Corporation 2004 Equity Incentive
Compensation Plan (the "Plan"), which is incorporated into and forms a part of
this Agreement, and the Participant has been selected by the Compensation
Committee of the Board of Directors of the Company which has been charged with
the responsibility of administering the Plan (the "Committee") to receive
Performance Units under the Plan;

      NOW, THEREFORE, IT IS AGREED, by and between the Company and the
Participant, as follows:

1.    Terms of Award. The following terms used in this Agreement shall have the
      meanings set forth in this paragraph 1:

      The "Participant" is NAME.

      The "Grant Date" is January 1, 2005.

      The "Determination Date" is December 31, 2006.

      The number of Performance Units granted under this Agreement is NUMBER.

      Other terms used in this Agreement are defined pursuant to paragraph 12 or
      elsewhere in this Agreement. Capitalized terms not defined herein shall
      have the meaning ascribed thereto in the Plan.

2.    Award. The Participant is hereby granted the number of Performance Units
      set forth in paragraph 1, subject to the terms of the Plan and this
      Agreement.

3.    Vesting, Transfer and Forfeiture Subject to the terms hereof, if, for each
      of the fiscal years during the period commencing on the Grant Date and
      ending on the Determination Date (the "Performance Period"), the Company's
      Total Gross Income less Gross Ownership Costs (as reported on the
      Company's audited income statement for the Performance Period) is greater
      than $325,000,000 (the "Threshold Goal"), then immediately following the
      Committee's certification that the Threshold Goal has been achieved, the
      Performance Units granted to a Participant shall be exchanged for shares
      of Restricted Common Stock ("Restricted Stock") in the form of "Earned
      Shares" and "Banked Shares" (as those terms are defined herein), the
      number of which shall be determined by the extent to which the Performance
      Goals set forth on Exhibit 1 have

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      been achieved during the Performance Period, and shall be calculated in
      the manner set forth on Exhibit 2 and the immediately following paragraph.

      If GATX fails to achieve a return on equity ("ROE") on a consolidated
      basis of at least 12% for the fiscal year ending on the Determination
      Date, the number of shares of Restricted Stock (calculated as set forth in
      the immediately preceding paragraph) to which the Participant may become
      entitled shall be reduced by a percentage (the "Reduction Percentage"), as
      follows:

<TABLE>
<CAPTION>
    ROE                   Reduction Percentage
    ---                   --------------------
<S>                       <C>
11% - 11.99%                       10%
10% - 10.99%                       15%
Less than 10%                      20%
</TABLE>

      The shares of Restricted Stock reduced pursuant to the immediately
      preceding paragraph (the "Banked Shares") will be held by the Company for
      up to two (2) years after the Determination Date. The remaining shares to
      which the Participant is entitled (viz., the difference between the number
      of shares calculated as set forth on Exhibit 2 and the number of Banked
      Shares) shall hereinafter be referred to as the "Earned Shares".

      (a)   Except as provided in paragraph (c), if the Participant's Date of
            Termination has not previously occurred, the Participant's Earned
            Shares shall vest on the first anniversary of the Determination
            Date, and shall be distributed as promptly thereafter as is
            reasonably practical free and clear of all restrictions

      (b)   If as of the first anniversary of the Determination Date, the
            Company achieves a ROE on a consolidated basis of at least ten
            percent (10%) for the fiscal year ending on such date, fifty percent
            (50%) of the Participant's Banked Shares shall vest, and shall be
            distributed free and clear of all restrictions promptly thereafter.
            If as of the first anniversary of the Determination Date, GATX does
            not achieve a ROE on a consolidated basis of at least ten percent
            (10%) for the fiscal year ending on such date, the Banked Shares
            shall continue to be held by the Company, subject to the immediately
            following sentence. If, as of the second anniversary of the
            Determination Date, GATX achieves a ROE on a consolidated basis of
            at least twelve percent (12%) for the fiscal year ending on such
            date, all Banked Shares not previously distributed shall vest, and
            shall be distributed free and clear of all restrictions promptly
            thereafter. Any Banked Shares which do not vest as of the second
            anniversary of the Determination Date shall be forfeited, and the
            Participant shall cease to have any rights therein.

      (c)   Notwithstanding the foregoing provisions of this paragraph 3, the
            Participant's Performance Units shall be exchanged for shares
            Restricted Stock and the Participant shall be vested therein, and
            become owner thereof free and clear of all restrictions otherwise
            imposed by this Agreement, as follows:

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            (i)   If the Participant's employment is involuntarily terminated by
                  the Company other than for Cause, not less than eighteen (18)
                  months following the Grant Date but on or prior to the first
                  anniversary of the Determination Date, he or she will be
                  entitled to a pro rata portion of his or her shares hereunder
                  equal in number to the product of the number of Earned Shares
                  to which the Participant becomes entitled or is entitled
                  pursuant to this paragraph 3, multiplied by a fraction (not
                  greater than one), the numerator of which is the number of
                  months the Participant is employed by the Company or its
                  subsidiaries during the period beginning on the Grant Date and
                  ending on the Date of Termination and the denominator of which
                  is the number of months in the Vesting Period. The Earned
                  Shares to which the Participant is entitled pursuant to this
                  subparagraph (i) shall be distributed to the Participant free
                  and clear of all restrictions as soon as practical following
                  the first anniversary of the Determination Date. If the
                  Participant's employment is involuntarily terminated by the
                  Company other than for Cause after the first anniversary of
                  the Determination Date, he or she shall have no rights to any
                  Banked Shares which are not then distributable, which shall be
                  forfeited.

            (ii)  If the Participant's Date of Termination occurs by reason of
                  the Participant's death, Retirement or Disability prior to the
                  Determination Date, he or she will be entitled to distribution
                  of a pro rata portion of his or her Restricted Stock free and
                  clear of all restrictions promptly following the Determination
                  Date, equal in number to the product of the number of Earned
                  Shares to which the Participant is entitled pursuant to this
                  paragraph 3, multiplied by a fraction (not greater than one),
                  the numerator of which is the number of months during the
                  period beginning on the Grant Date and ending on the date of
                  the Participant's death, Retirement or Disability and the
                  denominator of which is the number of months in the Vesting
                  Period. If the Participant's Date of Termination occurs by
                  reason of the Participant's death, Retirement or Disability
                  after the Determination Date, he or she shall have no rights
                  to any Banked Shares which are not distributable as of the
                  Date of Termination, which shall be forfeited. If a
                  Participant's Date of Termination occurs by reason of the
                  Participant's death, Retirement or Disability, as described in
                  the first sentence of this subparagraph (ii), the Committee
                  may, in its sole discretion, increase the number of Restricted
                  Stock to which the Participant is entitled.

            (iii) The Participant shall become fully vested in any undistributed
                  shares upon a Change in Control that occurs at the Company
                  level, on or before the Participant's Date of Termination and
                  before the second anniversary of the Determination Date. If
                  the Change of Control occurs at the Company level on or prior
                  to the Determination Date, the number of shares of common
                  stock to which the Participant is entitled shall be calculated
                  as if the Company had achieved 100% performance against goal
                  and a twelve percent ROE in the year immediately preceding the
                  Determination Date,

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                  and shall be distributed to the Participant free and clear of
                  all restrictions as soon as practicable following the Change
                  of Control. If the Change of Control occurs at the Company
                  level after the Determination Date, any previously
                  undistributed Earned Shares and all Banked Shares shall be
                  distributed to the Participant free and clear of all
                  restrictions as soon as practicable following the Change of
                  Control.

            (iv)  If a Change of Control occurs at the level of a subsidiary or
                  operating segment of the Company as the latter is defined in
                  the Company's most recent Annual Report on Form 10-K
                  (hereinafter, a "Business Segment") with respect to a
                  Participant principally employed by the subsidiary or who
                  renders substantially all of his or her services to such
                  Business Segment, such Participant shall become vested in his
                  or her shares (prior to the Determination Date, on the
                  assumption that the Company achieved both one hundred percent
                  (100%) performance against goal and a twelve percent (12%) ROE
                  in the year immediately preceding the Determination Date), as
                  follows:

                  (A)   If the Change of Control occurs during the first year of
                        the Vesting Period, the Participant shall be entitled to
                        receive common stock of the Company equal in number to
                        one-third (1/3) of his or her Performance Units.

                  (B)   If the Change of Control occurs during the second year
                        of the Vesting Period, the Participant shall be entitled
                        to receive common stock of the Company equal in number
                        to two-thirds (2/3) of his or her Performance Units.

                  (C)   If a Change of Control occurs after the Determination
                        Date, such Participant shall be entitled to common stock
                        of the Company equal in number to the total of all
                        undistributed Earned Shares and all Banked Shares.

            In each case distribution of shares free and clear of all
            restrictions shall be made as soon as practicable following the
            Change of Control.

      (d)   If the Participant's employment is terminated for Cause the
            Participant shall forfeit all non-vested Performance Units, any
            undistributed Earned Shares or Banked Shares and any rights under
            this Agreement.

      (e)   Neither the Performance Units, Earned Shares or Banked Shares may be
            sold, assigned, transferred, pledged or otherwise encumbered until
            the shares of shares have been distributed to the Participant free
            and clear of all restrictions.

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4.    Voting Rights and Dividends. Notwithstanding anything to the contrary, the
      Participant shall not be entitled to vote his or her Performance Units,
      but from and after the Determination Date shall be entitled to vote all
      Earned Shares.

      Unless a Participant's Date of Termination has occurred for any reason
      prior thereto, following the Determination Date an account shall be
      established for the Participant, to which shall be credited dividend
      equivalents equal to the product of (a) the sum of the Participant's
      Earned Shares and Banked Shares and (b) the dividend declared on a single
      share of the Company's Common Stock during the period beginning on the
      Grant Date and ending on the Date of Determination. Unless a Participant's
      Date of Termination shall have previously occurred, on each dividend
      payment date thereafter during the period beginning on the Determination
      Date, the Participant's account shall be credited with dividend
      equivalents equal to the product of (x) the sum of the Participant's then
      undistributed Earned Shares and Banked Shares and (y) the dividend
      declared on a single share of the Company's Common Stock with respect to
      the immediately preceding dividend record date. A Participant shall be
      entitled to a distribution of an amount equal to the dividend equivalents
      credited to his or her account and attributable to his or her Earned
      Shares or Banked Shares if and when he or she is entitled to distribution
      of such shares. The dividend equivalents attributable to forfeited Earned
      or Banked Shares shall likewise be forfeited.

5.    Withholding. The grant, vesting and distribution of benefits under this
      Agreement are subject to withholding of all applicable taxes. Subject to
      such rules and limitations as may be established by the Committee from
      time to time, the Participant may satisfy his or her withholding
      obligations through the surrender of shares of stock which the Participant
      already owns, or to which the Participant is otherwise entitled under the
      Plan; provided, however, that, except as otherwise provided by the
      Committee, such shares may be used to satisfy not more than the Company's
      minimum statutory withholding obligation (based on minimum statutory
      withholding rates for Federal and state tax purposes, including payroll
      taxes, that are applicable to such supplemental taxable income).

6.    Heirs and Successors. This Agreement shall be binding upon, and inure to
      the benefit of, the Company and its successors and assigns, and upon any
      person acquiring, whether by merger, consolidation, purchase of assets or
      otherwise, all or substantially all of the Company's assets and business.
      If any rights of the Participant or benefits distributable to the
      Participant under this Agreement have not been exercised or distributed,
      respectively, at the time of the Participant's death, such rights shall be
      exercisable by the Designated Beneficiary, and such benefits shall be
      distributed to the Designated Beneficiary, in accordance with the
      provisions of this Agreement and the Plan. If a deceased Participant fails
      to designate a beneficiary, or if the Designated Beneficiary does not
      survive the Participant, any rights that would have been exercisable by
      the Participant and any benefits distributable to the Participant shall be
      exercised by or distributed to the legal representative of the estate of
      the Participant. If the Designated Beneficiary survives the Participant
      but dies before the exercise of all rights or the complete distribution of
      benefits under this Agreement, then any remaining rights and any remaining
      benefit

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      distribution shall be exercisable by or distributed to the legal
      representative of the estate of the Designated Beneficiary.

7.    Administration. The authority to manage and control the operation and
      administration of this Agreement shall be vested in the Committee, and the
      Committee shall have all powers with respect to this Agreement as it has
      with respect to the Plan. Any interpretation of the Agreement by the
      Committee and any decision made by it with respect to the Agreement shall
      be final and binding on all persons.

8.    Plan Governs. Notwithstanding anything in this Agreement to the contrary,
      the terms of this Agreement shall be subject to the terms of the Plan, a
      copy of which may be obtained by the Participant from the Director,
      Compensation of the Company; and this Agreement is subject to all
      interpretations, amendments, rules and regulations promulgated by the
      Committee from time to time pursuant to the Plan.

9.    Not An Employment Contract. The Award will not confer on the Participant
      any right with respect to continuance of employment or other service with
      the Company or any subsidiary, nor will it interfere in any way with any
      right the Company or any subsidiary would otherwise have to terminate or
      modify the terms of such Participant's employment or other service at any
      time.

10.   Notices. Any written notices provided for in this Agreement or the Plan
      shall be in writing and shall be deemed sufficiently given if either hand
      delivered or if sent by fax or overnight courier, or by postage paid first
      class mail. Notices sent by mail shall be deemed received three business
      days after mailing but in no event later than the date of actual receipt.
      Notices shall be directed, if to the Participant, at the Participant's
      address indicated by the Company's records, or if to the Company, to the
      attention of the Director, Compensation at the Company's principal
      executive office.

11.   Amendment. This Agreement may be amended in accordance with the provisions
      of the Plan, and may otherwise be amended by written agreement of the
      parties.

12.   Definitions. For purposes of this Agreement, the terms used in this
      Agreement shall be subject to the following:

      Cause. The term "Cause" shall mean (i) the willful and continued failure
      of the Participant to perform the Participant's duties with the Company or
      one of its affiliates (other than any such failure resulting from
      incapacity due to physical or mental illness), or (ii) the willful
      engaging by the Participant in illegal conduct or gross misconduct in the
      course of his or her discharge of duties for the Company. For purposes of
      this provision, no act or failure to act, on the part of the Participant,
      shall be considered "willful" unless it is done, or omitted to be done, by
      the Participant in bad faith or without reasonable belief, that the
      Participant's action or omission was in the best interests of the Company.

      Change in Control. The term "Change in Control" shall have the meaning
      ascribed to it in Section 5 of the Plan.

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      Date of Termination. The term "Date of Termination" means the first day
      occurring on or after the Grant Date on which the Participant is not
      employed by the Company (or in the case of a non-employee member of the
      Board of Directors of the Company, is not a member on the Board) or any
      Subsidiary, regardless of the reason for the termination of employment;
      provided that a termination of employment shall not be deemed to occur by
      reason of a transfer of the Participant between the Company and a
      subsidiary or between two subsidiaries; and further provided that the
      Participant's employment shall not be considered terminated while the
      Participant is on a leave of absence from the Company or a subsidiary
      approved by the Participant's employer. If, as a result of a sale of
      assets, merger or other transaction, (i) the Participant's employer ceases
      to be a subsidiary (and the Participant's employer is or becomes an entity
      that is separate from the Company), and the Participant is not, at any
      time during the 30-day period following the transaction, employed by the
      Company or an entity that is then a subsidiary, or (ii) the business
      segment to which the Participants' responsibilities primarily relate
      immediately prior thereto as the subject of a sale or other transaction
      pursuant to which all or substantially all of the assets of such segment
      are sold, then the occurrence of such transaction shall be treated as the
      Participant's Date of Termination caused by the Participant being
      discharged by the employer.

      Disability. Except as otherwise provided by the Committee, the Participant
      shall be considered to have a "Disability" during the period in which the
      Participant is considered to be "disabled" as that term is defined in the
      Company's long term disability plan.

      Retirement. "Retirement" of the Participant means retirement on a
      "Retirement Date," as that term is defined in the GATX Corporation
      Non-Contributory Pension Plan for Salaried Employees (the "Pension Plan");
      provided that if the Participant is not a participant in the Pension Plan,
      the Retirement Date shall be the date determined by the Committee.

      Vesting Period. The term "Vesting Period" means the period beginning on
      the Grant Date and ending on the First Anniversary of the Determination
      Date.

      IN WITNESS WHEREOF, the Participant has executed this Agreement, and the
Company has caused these presents to be executed in its name and on its behalf,
all as of the Grant Date.

Participant: ______________________________

GATX Corporation

By:

Its: President and CEO

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