GATX Corporation leases, operates, manages, and remarkets assets in the rail and marine markets in North America and internationally. The company operates in four segments: Rail North America, Rail International, American Steamship Company (ASC), and Portfolio Management. The Rail North America segment primarily leases railcars and locomotive, as well as other ancillary services. This segment also offers repair, maintenance, modification, and regulatory compliance services on the railcar fleet. The Rail International segment leases railcars, as well as offers repair, regulatory compliance, and modernization work for railcars. The ASC segment operates a fleet of vessels that provide waterborne transportation of dry bulk commodities, such as iron ore, coal, limestone aggregates, and metallurgical limestone for steel makers, automobile manufacturing, electricity generation, and non-residential construction markets. The Portfolio Management segment is involved in leasing, asset remarketing, and marine operations, as well as manages portfolios of assets for third parties. As of December 31, 2015, it operated a fleet of 17 vessels; a fleet of approximately 106,100 cars; a fleet of 18,400 boxcars; and a fleet of 611 older four-axle and 26 six-axle locomotives. GATX Corporation was founded in 1898 and is headquartered in Chicago, Illinois.