UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 __________________________________________ FORM 10-Q __________________________________________ ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 ☐ Commission File Number: 1-2328 GATX Corporation (Exact name of registrant as specified in its charter) New Yor ...