USRA standard
The USRA standard locomotives and railroad cars were designed by the United States Railroad Administration, the nationalized rail system of the United States during World War I. 1,870 steam locomotives and over 100,000 railroad cars were built to these designs during the USRA's tenure. The locomotive designs in particular were the nearest the American railroads and locomotive builders ever got to standard locomotive types, and after the USRA was dissolved in 1920 many of the designs were duplicated in number, 3,251 copies being constructed overall. The last steam locomotive built for a Class I railroad in the United States, an 0-8-0 built by the Norfolk and Western Railway in 1953, was a USRA design. A total of 97 railroads used USRA or USRA-derived locomotives.