* Factory Assembled - Ready for Service * Non-Magnetic Blackened Metal Wheels * Free-Rolling 50-Ton Spring Plankless Trucks * AB Brake System * Magnetic Knuckle Couplers * 2 Styles of Handbrakes to Match Prototype Preference * 2 Styles of Door Locks to Match Prototype Preference * Fully Weighted for Trouble-Free Operation
 
In 1941, with direct U.S. involvement in World War II appearing increasingly likely, the Association of American Railroads car committee was instructed to develop a series of War Emergency freight cars in which wood would be employed where possible in place of sheet steel, which was in short supply. One of the designs that resulted was a composite version of the AAR standard twin hopper car. The AAR standard twin hopper car was a design that had been proposed in 1935 by the AAR car committee, and had become the standard fifty-ton twin hopper car in the preceding six years.
 
Almost 11,000 of these War Emergency fifty-ton composite twin hoppers were built between late 1942 and early 1945, making it the single most popular car of the War Emergency designs. The design duplicated that of the standard all-steel hopper in most respects but was distinctive in appearance because the side sheathing was wood and the side framing incorporated "hat" section pressed steel vertical and diagonal side posts. Following the war when steel was again plentiful, many railroads opted to replace the wood sides with steel for improved durability. Many War Emergency hoppers remained in revenue service into the 1960s, with many lasting into the 1970s.