In January 1949, the Silverton Tramway Company ordered two 4-8-2 locomotives from Beyer, Peacock & Co, Manchester, to the same design as the Western Australian Government Railways W class.

[1][2] All four arrived at Port Pirie in October 1951 and, after final assembly, moved to Broken Hill in a convoy, with two in steam.

Until 1953, all were hired to the South Australian Railways on a rotating basis, operating services out of Peterborough, until the South Australian Railways 400 class locomotives were delivered.

[2][3] The Silverton W class differed from the WAGR examples in having a skyline cowling running the length of the boiler and smokebox, Westinghouse air brakes, and an additional blow-down valve in the middle of the bottom of the boiler barrel.

The Pichi Richi Railway has a locomotive operating as W22, although it is actually W916 masquerading as W22, including some parts from the latter.