USRA standard

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The USRA standard

in 1953, was a USRA design. A total of 97 railroads used USRA or USRA-derived locomotives.

Steam locomotive types

The USRA developed designs for 0-6-0 and 0-8-0 switcher locomotives, 2-6-6-2 and 2-8-8-2 Mallet locomotives, and both light and heavy versions of the 2-8-2, 2-10-2, 4-6-2, and 4-8-2 types. The light versions were designed with an axle 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 distributed 2-10-0 Decapods of Russian design to railroads under its control.

255 of the USRA 0-6-0 design were built, as well as many copies.

175 of the USRA 0-8-0 design were built, and it was copied extensively thereafter.

614 of the USRA Light Mikado type were constructed, making it the most populous USRA type.

233 of the USRA Heavy Mikados were built.

94 USRA Light Santa Fe locomotives were constructed.

175 USRA Heavy Santa Fe locomotives were built.

106 USRA Light Pacifics were constructed.

20 USRA Heavy Pacifics were built.

47 of the USRA Light Mountain type were built.

15 USRA Heavy Mountains were constructed.

30 of the USRA 2-6-6-2 type were built.

106 of the USRA 2-8-8-2 locomotives were constructed. The Norfolk 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 common

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 like girder 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 like truss 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 of cars built by the USRA^[1]

Type	USRA Specification	Number of cars produced
50-ton Single-Sheathed Box Car	1001-B	25,000
50-ton Drop-Bottom Gondola	1002-B	20,000
40-ton Double-Sheathed Box Car	1003-B	25,000
55-ton Steel Twin Hopper	1005-B	5,000
70-ton Steel Drop-End Mill Gondola	1006-B	5,000