GATX CORP — Director's Dealing 2006

May 10, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: GATX CORP (GMT)
CIK: 0000040211
Period of Report: 2006-05-08

Reporting Person: HASEK WILLIAM J (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2006-05-08	Common Stock	M	2250	$39.7188	Acquired	5634	Direct
2006-05-08	Common Stock	M	3000	$39.4688	Acquired	8634	Direct
2006-05-08	Common Stock	M	6000	$39.145	Acquired	14634	Direct
2006-05-08	Common Stock	M	5000	$31.735	Acquired	19634	Direct
2006-05-08	Common Stock	M	2450	$24.365	Acquired	22084	Direct
2006-05-08	Common Stock	S	17155	$48.0982	Disposed	4929	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2006-05-08	1998 NQ Stock Option (Right to Buy)	$39.7188	M	2250	Disposed	2008-07-24	Common Stock (2250)	Direct
2006-05-08	1999 NQ Stock Option (Right to Buy)	$39.4688	M	3000	Disposed	2009-07-23	Common Stock (3000)	Direct
2006-05-08	2001 NQ Stock Option (Right to Buy)	$39.145	M	6000	Disposed	2011-07-27	Common Stock (6000)	Direct
2006-05-08	2002 NQ Stock Option (Right to Buy)	$31.735	M	5000	Disposed	2012-04-26	Common Stock (5000)	Direct
2006-05-08	2004 NQ Stock Option (Right to Buy)	$24.365	M	2450	Disposed	2011-08-06	Common Stock (2450)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock 401(k)	554.1	Indirect

Footnotes

F1: 50% of option granted may be exercised commencing 1 year from the date of the grant, an additional 25% commencing 2 years from the date of the grant and the remaining 25% commencing 3 years from the date of the grant.

F2: 50% of option granted may be exercised commencing 1 year from the date of the grant, an additional 25% commencing 2 years from the date of the grant and the remaining 25% commencing 3 years from the date of the grant.

F3: 50% of option granted may be exercised commencing 1 year from the date of the grant, an additional 25% commencing 2 years from the date of the grant and the remaining 25% commencing 3 years from the date of the grant.

F4: 50% of option granted may be exercised commencing 1 year from the date of the grant, an additional 25% commencing 2 years from the date of the grant and the remaining 25% commencing 3 years from the date of the grant.