<PAGE>   1
 
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JUNE 19, 1996
                                                      REGISTRATION NO. 33-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                               ------------------
 
                                    FORM S-8
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                               ------------------
                                GATX CORPORATION
             (Exact name of Registrant as specified in its charter)
 
<TABLE>
<S>                                           <C>
                   NEW YORK                                     36-1124040
           (State of incorporation)                 (IRS Employer Identification No.)
   500 W. MONROE STREET, CHICAGO, ILLINOIS                        60661
   (Address of principal executive offices)                     (Zip Code)
</TABLE>
 
                              GATX LOGISTICS INC.,
                         401(K) CASH ACCUMULATION PLAN
                            (Full Title of the Plan)
                            DAVID B. ANDERSON, ESQ.
                                GATX CORPORATION
                 500 W. MONROE STREET, CHICAGO, ILLINOIS 60661
                    (Name and address of agent for service)
  Telephone number, including area code, of agent for service: (312) 621-8472
                        CALCULATION OF REGISTRATION FEE
<TABLE>
<Captain>
- --------------------------------------------------------------------------------------------------
- --------------------------------------------------------------------------------------------------
 
                                                    PROPOSED         PROPOSED
                                     AMOUNT         MAXIMUM          MAXIMUM         AMOUNT OF
      TITLE OF SECURITIES            TO BE       OFFERING PRICE     AGGREGATE       REGISTRATION
       TO BE REGISTERED*          REGISTERED*     PER SHARE**    OFFERING PRICE**       FEE
<S>                             <C>             <C>             <C>               <C>
- --------------------------------------------------------------------------------------------------
Common Stock, $.625 Par Value...   200,000 shs.      $46.50         $9,300,300       $3,206.92
- --------------------------------------------------------------------------------------------------
- --------------------------------------------------------------------------------------------------
</TABLE>
 
 * Pursuant to Rule 416(c) under the Securities Act of 1933, this registration
   statement also covers an indeterminate amount of interests to be offered and
   sold pursuant to the Plan.
 
** Estimated solely for purpose of computing the registration fee pursuant to
   Rule 457 based on the average of the high and low prices reported on the New
   York Stock Exchange composite tape on June 17, 1996.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2
 
                                    PART II
 
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
 
     This Registration Statement covers 200,000 shares of common stock of GATX
Corporation; (the "Company") to be purchased from time to time under the GATX
Logistics Inc., 401(k) Cash Accumulation Plan (the "Plan") with salary deferrals
by participants who may elect to invest in the GATX Common Stock fund.
 
ITEM 3--INCORPORATION OF DOCUMENTS BY REFERENCE
 
     The following documents filed by the Company with the Securities and
Exchange Commission (the "Commission") are incorporated herein by reference:
 
          (a) The Company's Annual Report on Form 10-K for the year ended
     December 31, 1995.
 
          (b) The Company's Quarterly Report on Form 10-Q for the quarter ended
     March 31, 1996.
 
          (c) The description of the common stock, par value $.625 per share, of
     the Company (the "Common Stock") contained in the first paragraph of
     "Description of Capital Stock -- Common Stock" from the Company's
     Prospectus dated August 3, 1989, included as part of the Company's
     Registration Statement on Form S-3 filed with the Commission on August 3,
     1989 (No. 33-30165).
 
All documents subsequently filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act") prior to the filing of a post-effective amendment which
indicates all securities then remaining unsold, shall be deemed to be
incorporated herein by reference and shall be deemed a part hereof from the date
of the filing of such documents.
 
ITEM 4--DESCRIPTION OF SECURITIES
 
     Not Applicable.
 
ITEM 5--INTERESTS OF NAMED EXPERTS AND COUNSEL
 
     Not Applicable.
 
ITEM 6--INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     Certain provisions of the New York Business Corporation Law and Article II,
Section 11 of the Company's by-laws provide for indemnification of directors and
officers under certain conditions, including the possibility of indemnification
against liabilities under the Securities Act. In addition, the Company has a
directors and officers liability insurance policy.
 
ITEM 7--EXEMPTION FROM REGISTRATION CLAIMED
 
     Not Applicable.
 
ITEM 8--EXHIBITS
 
     See Exhibit Index which is incorporated by reference.
 
     The Company has submitted or will submit the Plan and any amendment thereto
to the Internal Revenue Service ("IRS") in a timely manner, and has made or will
make all changes required by the IRS in order to qualify the Plan.
 
                                      II-1
<PAGE>   3
 
ITEM 9--UNDERTAKINGS
 
     The Company hereby undertakes:
 
          1. To file, during any period in which offers or sales are being made,
     a post-effective amendment to this registration statement:
 
             (i) To include any prospectus required by Section 10(a)(3) of the
        Securities Act of 1933 (the "Securities Act");
 
             (ii) To reflect in the prospectus any facts or events arising after
        the effective date of the registration statement (or the most recent
        post-effective amendment thereof) which, individually or in the
        aggregate, represent a fundamental change in the information set forth
        in the registration statement. Notwithstanding the foregoing, any
        increase or decrease in volume of securities offered (if the total
        dollar value of securities offered would not exceed that which was
        registered) and any deviation from the low or high end of the estimated
        maximum offering range may be reflected in the form of prospectus filed
        with the Commission pursuant to Rule 424(b) if, in the aggregate, the
        changes in the volume and price represent no more than a 20% change in
        the maximum aggregate offering price set forth in the "Calculation of
        Registration Fee" table in the effective registration statement;
 
             (iii) To include any material information with respect to the plan
        of distribution not previously disclosed in the registration statement
        or any material change to such information in the registration
        statement;
 
     Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if
     the registration statement is on Form S-3 or Form S-8, and the information
     required to be included in a post-effective amendment by those paragraphs
     is contained in periodic reports filed by the Company pursuant to Section
     13 or Section 15 of the Exchange act that are incorporated by reference to
     the registration statement.
 
          2. That, for purpose of determining any liability under the Securities
     Act, each such post-effective amendment shall be deemed to be a new
     registration statement relating to the securities offered therein, and the
     offering of such securities at that time shall be deemed to be the initial
     bona fide offering thereof.
 
          3. To remove from registration by means of a post-effective amendment
     any of the securities being registered which remain unsold at the
     termination of the offering.
 
     The Company hereby further undertakes that, for purpose of determining any
liability under the Securities Act, each filing of the Company's annual report
pursuant to section 13(a) or section 15(d) of the Exchange Act (and, where
applicable, each filing of any employee benefit plan's annual report pursuant to
section 15(d) of the Exchange Act) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at the time shall be deemed to be the initial bona fide offering thereof.
 
     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the provisions referred to in Item 6 or otherwise, the
Company has been advised that in the opinion of the Commission, such
indemnification is against public policy as expressed in the Securities Act, and
is therefore unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Company of expenses
incurred or paid by a director, officer or controlling person of the Company in
the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question of whether such indemnification by it is against
public policy as expressed in the Securities Act and will be governed by the
final adjudication of such issue.
 
                                      II-2
<PAGE>   4
 
                                   SIGNATURES
 
     The Registrant. Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Chicago, and the State of Illinois, on this 19th day
of June 1996.
 
                                            GATX Corporation
 
                                            By      /s/ WILLIAM L. CHAMBERS
 
                                             -----------------------------------
                                                     William L. Chambers
                                               Vice President, Human Resources
 
     PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS
REGISTRATION STATEMENT HAS BEEN SIGNED BELOW BY THE FOLLOWING PERSONS IN THE
CAPACITIES AND ON THE DATES INDICATED.
 
<TABLE>
<CAPTION>
                  SIGNATURE                                         TITLE
- ---------------------------------------------   ----------------------------------------------
<C>                                             <S>
                      *                         Chairman of the Board and Chief Executive
- ---------------------------------------------     Officer (Principal Executive Officer)
               Ronald H. Zech
            /s/ DAVID M. EDWARDS                Vice President and Chief Financial Officer
- ---------------------------------------------     (Principal Financial Officer)
              David M. Edwards
             /s/ RALPH L. O'HARA                Controller (Principal Accounting Officer)
- ---------------------------------------------
               Ralph L. O'Hara
                      *                         Director
- ---------------------------------------------
              Franklin A. Cole
                      *                         Director
- ---------------------------------------------
               James M. Denny
                      *                         Director
- ---------------------------------------------
              William C. Foote
                      *                         Director
- ---------------------------------------------
              Deborah M. Fretz
                      *                         Director
- ---------------------------------------------
              Richard A. Giesen
                      *                         Director
- ---------------------------------------------
               Miles L. Marsh
                      *                         Director
- ---------------------------------------------
              Charles Marshall
                      *                         Director
- ---------------------------------------------
              Michael E. Murphy
        *By:  /s/ RONALD J. CIANCIO
- ---------------------------------------------
              Ronald J. Ciancio
              Attorney in Fact
            Dated: June 19, 1996
</TABLE>
 
                                      II-3
<PAGE>   5
 
     THE PLAN. Pursuant to the requirements of the Securities Act of 1933, the
plan has caused this registration statement to be signed on its behalf by the
undersigned, thereunto duly authorized in the City of Chicago and the State of
Illinois on this 19th day of June, 1996.
                                          GATX LOGISTICS INC.,
                                          401(k) CASH ACCUMULATION PLAN
                                          by Administrative Committee
                                          (Plan Administrator)
 
                                          By          /s/ RONALD PETERCA
 
                                            ------------------------------------
                                                       Ronald Peterca
                                                     Authorized Member
 
                                      II-4
<PAGE>   6
 
                                                      EXHIBIT INDEX
 
<TABLE>
<CAPTION>
EXHIBIT                                                                             SEQUENTIAL
NUMBER                            DESCRIPTION OF EXHIBIT                            PAGE NUMBER
- ------    -----------------------------------------------------------------------   -----------
<C>       <S>                                                                       <C>
  4.1     Restated Certificate of Incorporation of GATX Corporation, as amended,
          filed as Exhibit 3(a) to the Company's Annual Report on Form 10-K for
          the year ended December 31, 1991, and incorporated herein by reference
  4.2     By-Laws of GATX Corporation, as amended and restated as of July 29,
          1994, filed as Exhibit 3(b) to the Company's Annual Report on Form 10-K
          for the year ended December 31, 1994, and incorporated herein by
          reference
  4.3     GATX Logistics Inc., 401(k) Cash Accumulation Plan
 23       Consent of Ernst & Young LLP...........................................
 24       Powers of Attorney.....................................................
</TABLE>
 
                                      II-5
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 15732}]
{"company-data": {"conformed-name": "GATX CORP", "cik": "0000040211", "assigned-sic": "4700", "irs-number": "361124040", "state-of-incorporation": "NY", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-06315", "film-number": "96583127"}, "business-address": {"street1": "120 S RIVERSIDE PLZ", "city": "CHICAGO", "state": "IL", "zip": "60606", "phone": "3126216200"}, "former-company": {"former-conformed-name": "GENERAL AMERICAN TRANSPORTATION CORP", "date-changed": "19750722"}}
1
 
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JUNE 19, 1996
                                                      REGISTRATION NO. 33-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                               ------------------
 
                                    FORM S-8
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                               ------------------
                                GATX CORPORATION
             (Exact name of Registrant as specified in its charter)
NEW YORK                                     36-1124040
           (State of incorporation)                 (IRS Employer Identification No.)
   500 W. MONROE STREET, CHICAGO, ILLINOIS                        60661
   (Address of principal executive offices)                     (Zip Code)
GATX LOGISTICS INC.,
                         401(K) CASH ACCUMULATION PLAN
                            (Full Title of the Plan)
                            DAVID B. ANDERSON, ESQ.
                                GATX CORPORATION
                 500 W. MONROE STREET, CHICAGO, ILLINOIS 60661
                    (Name and address of agent for service)
  Telephone number, including area code, of agent for service: (312) 621-8472
                        CALCULATION OF REGISTRATION FEE
- --------------------------------------------------------------------------------------------------
- --------------------------------------------------------------------------------------------------
 
                                                    PROPOSED         PROPOSED
                                     AMOUNT         MAXIMUM          MAXIMUM         AMOUNT OF
      TITLE OF SECURITIES            TO BE       OFFERING PRICE     AGGREGATE       REGISTRATION
       TO BE REGISTERED*          REGISTERED*     PER SHARE**    OFFERING PRICE**       FEE
- --------------------------------------------------------------------------------------------------
Common Stock, $.625 Par Value...   200,000 shs.      $46.50         $9,300,300       $3,206.92
- --------------------------------------------------------------------------------------------------
- --------------------------------------------------------------------------------------------------
* Pursuant to Rule 416(c) under the Securities Act of 1933, this registration
   statement also covers an indeterminate amount of interests to be offered and
   sold pursuant to the Plan.
 
** Estimated solely for purpose of computing the registration fee pursuant to
   Rule 457 based on the average of the high and low prices reported on the New
   York Stock Exchange composite tape on June 17, 1996.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
2
 
                                    PART II
 
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
 
     This Registration Statement covers 200,000 shares of common stock of GATX
Corporation; (the "Company") to be purchased from time to time under the GATX
Logistics Inc., 401(k) Cash Accumulation Plan (the "Plan") with salary deferrals
by participants who may elect to invest in the GATX Common Stock fund.
 
ITEM 3--INCORPORATION OF DOCUMENTS BY REFERENCE
 
     The following documents filed by the Company with the Securities and
Exchange Commission (the "Commission") are incorporated herein by reference:
 
          (a) The Company's Annual Report on Form 10-K for the year ended
     December 31, 1995.
 
          (b) The Company's Quarterly Report on Form 10-Q for the quarter ended
     March 31, 1996.
 
          (c) The description of the common stock, par value $.625 per share, of
     the Company (the "Common Stock") contained in the first paragraph of
     "Description of Capital Stock -- Common Stock" from the Company's
     Prospectus dated August 3, 1989, included as part of the Company's
     Registration Statement on Form S-3 filed with the Commission on August 3,
     1989 (No. 33-30165).
 
All documents subsequently filed by the Company pursuant to Sections 13(a),
13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act") prior to the filing of a post-effective amendment which
indicates all securities then remaining unsold, shall be deemed to be
incorporated herein by reference and shall be deemed a part hereof from the date
of the filing of such documents.
 
ITEM 4--DESCRIPTION OF SECURITIES
 
     Not Applicable.
 
ITEM 5--INTERESTS OF NAMED EXPERTS AND COUNSEL
 
     Not Applicable.
 
ITEM 6--INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
     Certain provisions of the New York Business Corporation Law and Article II,
Section 11 of the Company's by-laws provide for indemnification of directors and
officers under certain conditions, including the possibility of indemnification
against liabilities under the Securities Act. In addition, the Company has a
directors and officers liability insurance policy.
 
ITEM 7--EXEMPTION FROM REGISTRATION CLAIMED
 
     Not Applicable.
 
ITEM 8--EXHIBITS
 
     See Exhibit Index which is incorporated by reference.
 
     The Company has submitted or will submit the Plan and any amendment thereto
to the Internal Revenue Service ("IRS") in a timely manner, and has made or will
make all changes required by the IRS in order to qualify the Plan.
 
                                      II-1
3
 
ITEM 9--UNDERTAKINGS
 
     The Company hereby undertakes:
 
          1. To file, during any period in which offers or sales are being made,
     a post-effective amendment to this registration statement:
 
             (i) To include any prospectus required by Section 10(a)(3) of the
        Securities Act of 1933 (the "Securities Act");
 
             (ii) To reflect in the prospectus any facts or events arising after
        the effective date of the registration statement (or the most recent
        post-effective amendment thereof) which, individually or in the
        aggregate, represent a fundamental change in the information set forth
        in the registration statement. Notwithstanding the foregoing, any
        increase or decrease in volume of securities offered (if the total
        dollar value of securities offered would not exceed that which was
        registered) and any deviation from the low or high end of the estimated
        maximum offering range may be reflected in the form of prospectus filed
        with the Commission pursuant to Rule 424(b) if, in the aggregate, the
        changes in the volume and price represent no more than a 20% change in
        the maximum aggregate offering price set forth in the "Calculation of
        Registration Fee" table in the effective registration statement;
 
             (iii) To include any material information with respect to the plan
        of distribution not previously disclosed in the registration statement
        or any material change to such information in the registration
        statement;
 
     Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if
     the registration statement is on Form S-3 or Form S-8, and the information
     required to be included in a post-effective amendment by those paragraphs
     is contained in periodic reports filed by the Company pursuant to Section
     13 or Section 15 of the Exchange act that are incorporated by reference to
     the registration statement.
 
          2. That, for purpose of determining any liability under the Securities
     Act, each such post-effective amendment shall be deemed to be a new
     registration statement relating to the securities offered therein, and the
     offering of such securities at that time shall be deemed to be the initial
     bona fide offering thereof.
 
          3. To remove from registration by means of a post-effective amendment
     any of the securities being registered which remain unsold at the
     termination of the offering.
 
     The Company hereby further undertakes that, for purpose of determining any
liability under the Securities Act, each filing of the Company's annual report
pursuant to section 13(a) or section 15(d) of the Exchange Act (and, where
applicable, each filing of any employee benefit plan's annual report pursuant to
section 15(d) of the Exchange Act) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at the time shall be deemed to be the initial bona fide offering thereof.
 
     Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the provisions referred to in Item 6 or otherwise, the
Company has been advised that in the opinion of the Commission, such
indemnification is against public policy as expressed in the Securities Act, and
is therefore unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Company of expenses
incurred or paid by a director, officer or controlling person of the Company in
the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Company will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question of whether such indemnification by it is against
public policy as expressed in the Securities Act and will be governed by the
final adjudication of such issue.
 
                                      II-2
4
 
                                   SIGNATURES
 
     The Registrant. Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Chicago, and the State of Illinois, on this 19th day
of June 1996.
 
                                            GATX Corporation
 
                                            By      /s/ WILLIAM L. CHAMBERS
 
                                             -----------------------------------
                                                     William L. Chambers
                                               Vice President, Human Resources
 
     PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, THIS
REGISTRATION STATEMENT HAS BEEN SIGNED BELOW BY THE FOLLOWING PERSONS IN THE
CAPACITIES AND ON THE DATES INDICATED.
SIGNATURE                                         TITLE
- ---------------------------------------------   ----------------------------------------------
*                         Chairman of the Board and Chief Executive
- ---------------------------------------------     Officer (Principal Executive Officer)
               Ronald H. Zech
            /s/ DAVID M. EDWARDS                Vice President and Chief Financial Officer
- ---------------------------------------------     (Principal Financial Officer)
              David M. Edwards
             /s/ RALPH L. O'HARA                Controller (Principal Accounting Officer)
- ---------------------------------------------
               Ralph L. O'Hara
                      *                         Director
- ---------------------------------------------
              Franklin A. Cole
                      *                         Director
- ---------------------------------------------
               James M. Denny
                      *                         Director
- ---------------------------------------------
              William C. Foote
                      *                         Director
- ---------------------------------------------
              Deborah M. Fretz
                      *                         Director
- ---------------------------------------------
              Richard A. Giesen
                      *                         Director
- ---------------------------------------------
               Miles L. Marsh
                      *                         Director
- ---------------------------------------------
              Charles Marshall
                      *                         Director
- ---------------------------------------------
              Michael E. Murphy
        *By:  /s/ RONALD J. CIANCIO
- ---------------------------------------------
              Ronald J. Ciancio
              Attorney in Fact
            Dated: June 19, 1996
II-3
5
 
     THE PLAN. Pursuant to the requirements of the Securities Act of 1933, the
plan has caused this registration statement to be signed on its behalf by the
undersigned, thereunto duly authorized in the City of Chicago and the State of
Illinois on this 19th day of June, 1996.
                                          GATX LOGISTICS INC.,
                                          401(k) CASH ACCUMULATION PLAN
                                          by Administrative Committee
                                          (Plan Administrator)
 
                                          By          /s/ RONALD PETERCA
 
                                            ------------------------------------
                                                       Ronald Peterca
                                                     Authorized Member
 
                                      II-4
6
 
                                                      EXHIBIT INDEX
EXHIBIT                                                                             SEQUENTIAL
NUMBER                            DESCRIPTION OF EXHIBIT                            PAGE NUMBER
- ------    -----------------------------------------------------------------------   -----------
4.1     Restated Certificate of Incorporation of GATX Corporation, as amended,
          filed as Exhibit 3(a) to the Company's Annual Report on Form 10-K for
          the year ended December 31, 1991, and incorporated herein by reference
  4.2     By-Laws of GATX Corporation, as amended and restated as of July 29,
          1994, filed as Exhibit 3(b) to the Company's Annual Report on Form 10-K
          for the year ended December 31, 1994, and incorporated herein by
          reference
  4.3     GATX Logistics Inc., 401(k) Cash Accumulation Plan
 23       Consent of Ernst & Young LLP...........................................
 24       Powers of Attorney.....................................................
II-5