The South African Railways Class 19D 4-8-2 of 1937 was a steam locomotive. Between 1937 and 1949, the South African Railways placed 235 Class 19D steam locomotives with a 4-8-2 Mountain type wheel arrangement in service. Between 1951 and 1955, 33 more were built for other operators like the Rhodesia and Angolan railways and the Nkana and Wankie mines, which makes the Class 19D the most numerous South African steam locomotive type ever built. Manufacturers The Class 19D 4-8-2 steam locomotive was the final development of the Class 19 family of locomotives. At the request of Colonel F.R. Collins, Chief Mechanical Engineer (CME) of the South African Railways (SAR) from 1922 to 1929, the original basic design of the Class 19 was done in the late 1920s by Test Engineer M.M. Loubser, who was himself later to serve as the CME from 1939 to 1949. The final development of the Class was done in 1937 by W.A.J. Day, CME from 1936 to 1939. The Class 19D was a revised version of the Class 19C with piston valves and Walschaerts valve gear instead of rotary cam poppet valve gear. Between 1937 and 1955, 268 Class 19D locomotives were built in seven batches by six locomotive manufacturers in Czechoslovakia, Germany and the United Kingdom and delivered to the SAR and several other operators in Southern Africa. The first forty were built in Germany in 1937, twenty with domeless boilers by Friedrich Krupp in Essen and numbered in the range from 2506 to 2525, and twenty by the Borsig Lokomotiv Werke in Hennigsdorf, Berlin and numbered in the range from 2526 to 2545. In 1938, a further 95 locomotives were ordered, built by three manufacturers. Škoda Works in Czechoslovakia built fifteen numbered in the range from 2626 to 2640, Krupp built forty, this time with domed boilers and numbered in the range from 2641 to 2680, and Borsig built forty numbered in the range from 2681 to 2720. Locomotive building was interrupted by World War II and post-war locomotive procurement saw European suppliers being replaced by British ones. In 1947, the first fifty post-war Class 19D locomotives were delivered by Robert Stephenson & Hawthorns (RSH) of Darlington, England and numbered in the range from 2721 to 2770. Of this order, engine no. 2734, RSH works no. 7247, was lost at sea off the east coast of England. Its replacement with RSH works number