GATX Corporation is a railcar lessor that owns fleets in North America, Europe, and Asia. In addition, jointly with Rolls-Royce Limited, it owns one of the largest aircraft spare engine lease portfolios. It is headquartered in Chicago, Illinois. As of December 31, 2020, the company owned 148,939 rail cars, including 83,959 tank cars, 64,980 freight cars, and 645 locomotives. Other major car types owned include covered hoppers, open-top hopper cars, and gondolas. It primarily serves the petroleum industry, chemical industry, food industry, mining industry, and transportation industry.
The following is a brief history of the North American rail system, mainly through major changes to Class I railroads, the largest class by operating revenue.