GATX Corp. (NYSE: GMT) is buying boxcars from GE Capital Rail Services for $340 million.

Chicago-based GATX, which provides railcar leasing services, is adding more than 18,500 boxcars from GE Capital's North American fleet in the deal. The transaction allows GATX to become a leader in the boxcar leasing market.

The company says many of the customers that use the fleet it is buying are already GATX customers.

The buyer expects to generate about $70 million in annual revenue because of the new fleet.

GE Capital Rail Services, also headquartered in Chicago, provides railcar leasing, maintenance and compliance services.

Other recent transportation deals include Roadrunner Transportation Systems Inc.'s (NYSE: RRTS) purchase of Unitrans International Logistics in March,