<SEC-DOCUMENT>0001246360-12-001322.txt : 20120228
<SEC-HEADER>0001246360-12-001322.hdr.sgml : 20120228
<ACCEPTANCE-DATETIME>20120228122014
ACCESSION NUMBER:		0001246360-12-001322
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20120225
FILED AS OF DATE:		20120228
DATE AS OF CHANGE:		20120228

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GATX CORP
		CENTRAL INDEX KEY:			0000040211
		STANDARD INDUSTRIAL CLASSIFICATION:	TRANSPORTATION SERVICES [4700]
		IRS NUMBER:				361124040
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		222 WEST ADAMS STREET
		CITY:			CHICAGO
		STATE:			X1
		ZIP:			60606-5314
		BUSINESS PHONE:		3126216200

	MAIL ADDRESS:	
		STREET 1:		222 WEST ADAMS STREET
		CITY:			CHICAGO
		STATE:			X1
		ZIP:			60606-5314

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	GENERAL AMERICAN TRANSPORTATION CORP
		DATE OF NAME CHANGE:	19750722

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MUCKIAN WILLIAM M
		CENTRAL INDEX KEY:			0001204289

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-02328
		FILM NUMBER:		12645545

	MAIL ADDRESS:	
		STREET 1:		500 WEST MONROE ST
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60661
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-02-25</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000040211</issuerCik>
        <issuerName>GATX CORP</issuerName>
        <issuerTradingSymbol>GMT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204289</rptOwnerCik>
            <rptOwnerName>MUCKIAN WILLIAM M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 W. ADAMS ST.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Sr. VP and Controller</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock 401(k)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5407.152</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(k) Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-02-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>162</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>43.37</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11940</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">GATX Corporation's 401(k) plan is a unitized stock fund made up of company stock plus short term investments. Because the fund includes more than company stock, participants purchase units of the fund rather than company shares of stock. The number of units held by a participant may vary depending on the performance of the company stock, the overall stock market, and the amount of short term investments in the fund. Such a variance has caused the value of the units in the reporting person's 401(k) fund to be reduced without any actual disposition of shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Lisa M. Ibarra, by Power of Attorney on behalf of William M. Muckian</signatureName>
        <signatureDate>2012-02-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
