In 1974 the TTX company formed a subsidiary, American Rail Box Car Company, to manage a pool of free-running 50' box cars bearing ABOX and RBOX reporting marks. This fleet of leased box cars could be freely assigned to railroads as needed, circumventing ICC directives to move empty cars in the direction of their owning roads. Railbox relied on individual guarantees from railroads to repair tracks and made use of contract repair facilities throughout the country to maintain the cars. The company also employed a variety of builders to construct the cars which were equipped with standardized, readily available parts in-order to simplify maintenance.