GATX CORP — Director's Dealing 2004

May 7, 2004

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: GATX CORP (GMT)
CIK: 0000040211
Period of Report: 2004-05-05

Reporting Person: MUCKIAN WILLIAM M (Vice President-Controller)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2004-05-05	Common Stock	M	3000.00	$20.9063	Acquired	4029.28	Direct
2004-05-05	Common Stock	S	3000.00	$24.418	Disposed	1029.28	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2004-05-05	1994 NQ Stock Option (right to buy)	$20.9063	M	3000	Disposed	2004-10-28	Common Stock (3000)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock - 401(k)	4006.80	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 th
e date of the grant and the remaining 25% commencing 3 years from the date of the grant.