Exhibit 99.1 NEWS RELEASE FOR IMMEDIATE RELEASE GATX CORPORATION REPORTS 2025 SECOND-QUARTER RESULTS CHICAGO, July 29, 2025—GATX Corporation (NYSE: GATX) today reported 2025 second-quarter net income of $75.5 million, or$2.06 per diluted share, compared to net income of $44.4 million, or$1.21 per diluted share, in the second quarter of 2024. The 2024 second-quarter results include a net negative impact of $8.0 million, or$0.22 per diluted share, from Tax Adjustments and Other Items. Net income for the fi ...