The 1937 AAR 40' boxcar is widely accepted as the freight car design that ushered in mass standardization of railroad rolling stock. Prior to the cars' introduction, standardization was minimal mostly due to Government control of the railroads. Once control was lifted, railroads returned to designs that most suited their needs. With economic uncertainty growing in the 1930s however, railroads realized the need for the economic benefits of standardized production processes and the effect that would have on lowering costs. The 1937 AAR boxcar was created as a result. With production numbers in the tens of thousands, these cars were seen in all types of service throughout North America from the late 1930s into the 1970s. The car had an interior length of 40 feet, 6 inches, and an interior height of 10 feet 0 inches resulting in a car with a 3,700 cubic foot capacity. Other features typically are seen on the majority of these cars were Dreadnaught ends, a straight panel "Murphy" roof, and 50-ton trucks with cast side frames. There were variations including the NSC-2 and Deco ends. For the first time, InterMountain is offering these two distinctive ends on its current run of cars (March 2020). Canadian National and Ontario Northland feature the NSC-2 ends, Chesapeake and Ohio (two different schemes), and Baltimore and Ohio have the Deco ends. As with all InterMountain offerings, these cars feature accurate laser printing, InterMountain metal wheels, and metal knuckle couplers.