The SR USA class are ex-United States Army Transportation Corps S100 Class 0-6-0 tank engine steam locomotives purchased and adapted by the Southern Railway (SR) after the end of the Second World War to replace the aging LSWR B4 class.
For fifteen years the entire class was used for shunting and van heating in Southampton Docks. They performed well and were popular with the footplate men, but the limited bunker capacity often necessitated the provision of relief engines for some of the longer duties. The SR crews operating these engines nicknamed them "Yank Tanks".
Starting out life as USA Class No. 1971, this locomotive was built in 1943 by Vulcan Iron Works and served the SR as No. 68 in their fleet. Upon nationalization of the railways in 1948, it was renumbered once again and became British Railways (BR) No. 30068.
No. 30068 was allocated to 71I Southampton Docks and eventually ended up at 71A Eastleigh Shed. It was withdrawn from service at the end of 1963 and was scrapped in 1964 at Eastleigh Works.