The original USRA (United States Railway Administration) design box cars date from World War I when car designs began to be standardized. The double sheathed version was the first widely accepted 40-foot steel underframe box cars placed in service. Some 24,500 cars were delivered to 24 different railroads throughout the country.
5-5-5 or 7-8 steel ends
Fishbelly or standard center sill
Vertical or end mounted brakes
Steel or wood doors