A goal of the American Railway Association (40' ARA) in the early 1920s was to produce an all-steel box car that could be recognized as a standard by the member railroads. Although the original design presented in 1923 produced in excess of 60,000 cars, it wasn't until a new design was presented in 1932 that the member railroads gave their approval.
After extensively testing five prototypes in 1933, over 14,500 cars were produced for twenty-three railroads throughout the following decade. This design soon evolved into the 1937, Modified 1937, and Postwar AAR box cars.
Although not the most popular design produced, numerically speaking, the 1932 40' ARA Standard box car is considered one of the most important designs in railroad history.