War Department

War Department locomotives — built in two world wars by British railway workshops and private contractors to government account — represent some of the most historically significant locomotive classes in British railway history, their design and deployment connecting the railway industry directly to the strategic requirements of industrial warfare. In the First World War the dominant type was the ROD 2-8-0, based on John G. Robinson's Great Central Railway 8K freight design of 1911, adopted by the Railway Operating Division as its standard locomotive and built in 521 examples for service across France, Egypt, Mesopotamia, and beyond.

In the Second World War R.A. Riddles designed the WD Austerity 2-8-0 — a deliberately simplified heavy freight engine capable of mass production under wartime conditions, stripped of all non-essential features while retaining adequate power for the military's haulage requirements. 935 were built by North British Locomotive Company, Vulcan Foundry, Beyer Peacock, and the LNER's Doncaster Works — a manufacturing achievement that demonstrated the British locomotive industry's capacity for wartime production. A matching WD Austerity 2-10-0 was designed for heavier requirements. After the war many WD locomotives entered British Railways service while others served on overseas railways into the 1980s and beyond — the Greek and Hong Kong railways among the last to retire them.