The USRA Light Mikado was a USRA standard class of steam locomotive designed under the control of the United States Railroad Administration, the nationalized railroad system in the United States during World War I. This was the standard light freight locomotive of the USRA types, and was of 2-8-2 wheel arrangement in the Whyte notation, or 1'D1' in UIC classification.
A total of 614 locomotives were built under the auspices of the USRA,[1] with a further 641 copies built after the end of the USRA's control. The first, for the Baltimore and Ohio Railroad, was completed in July 1918 and given #4500. The locomotives were considered well designed and modern, and were popular and successful. Large numbers remained in service until replaced by diesel locomotives. It was also called the McAdoo Mikado after William Gibbs McAdoo, head of the USRA.
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