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TheUSRA standardlocomotives andrailroad cars were designed by theUnited States Railroad Administration, thenationalized rail system of theUnited States duringWorld War I. 1,870steam 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 Americanrailroads andlocomotive 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 aClass I railroad in the United States, an0-8-0 built by theNorfolk and Western Railway in 1953, was a USRA design. A total of 97 railroads used USRA or USRA-derived locomotives.
The USRA developed designs for0-6-0 and0-8-0switcher locomotives,2-6-6-2 and2-8-8-2Mallet locomotives, and both light and heavy versions of the2-8-2,2-10-2,4-6-2, and4-8-2 types. The light versions were designed with anaxle load of 54,000 lb (24,500 kg) permitting usage on the vast majority of railroads, while the heavy versions were designed to a maximum axle load of 60,000 lb (27,200 kg) for lines with more heavily constructed track.
The U.S.R.A. also distributed2-10-0 Decapods of Russian design to railroads under its control.
255 of theUSRA 0-6-0 design were built, as well as many copies.
175 of theUSRA 0-8-0 design were built, and it was copied extensively thereafter.
614 of theUSRA Light Mikado type were constructed, making it the most populous USRA type.
233 of theUSRA Heavy Mikados were built.
94USRA Light Santa Fe locomotives were constructed.
175USRA Heavy Santa Fe locomotives were built.
106USRA Light Pacifics were constructed.
20USRA Heavy Pacifics were built.
47 of theUSRA Light Mountain type were built.
15USRA Heavy Mountains were constructed.
30 of theUSRA 2-6-6-2 type were built.
106 of theUSRA 2-8-8-2 locomotives were constructed. TheNorfolk and Western Railway, in particular, continued building this type after the USRA period, developing and modernising it over time, as its Class Y. A N&W Y6B was the last conventional freight-hauling steam locomotive built in the United States.
As part of the USRA, two commonboxcar designs were developed: a single sheathed car and a double sheathed car. When the USRA boxcars were being designed there wasn't an industry consensus on which was better, so both were built. Freight car design was still in flux in the early part of the 20th century. As John White points out inThe American Freight Car, most cars were really composites, not completelywood orsteel, and even after steel cars had become the norm, wood had its uses and advantages. Still, steelunderframes had come to replace wood underframes, but asmetallurgy improved, there were new designs developed that took advantage of the improved technology. USRA double sheathed boxcars had a fishbelly underframe while the USRA single sheathed cars did not. In general, double sheathed boxcars are likegirder bridges, so all the support needs to come from the frame. Those cars need a stronger frame, hence the fishbelly underframe. Single sheathed cars are liketruss bridges, with the metal side bracing acting as the main structural support for the "bridge." While some engineers did not trust the steel bracing to support a single sheathed car and ordered fishbelly frames for strength, others valued the savings in weight and ordered cars with simpler frames like the USRA SS design.
| Type | USRA Specification | Number of cars produced |
|---|---|---|
| 50-ton Single-Sheathed Box Car | 1001-B | 25,000 |
| 50-ton Drop-BottomGondola | 1002-B | 20,000 |
| 40-ton Double-Sheathed Box Car | 1003-B | 25,000 |
| 55-ton Steel TwinHopper | 1005-B | 5,000 |
| 70-ton Steel Drop-End Mill Gondola | 1006-B | 5,000 |
