In 1924, the South Australian Railways ordered ten 4-6-2 locomotives from Armstrong Whitworth in Britain which were based on the USRA Light Pacific. They had to be modified to fit the smaller Australian loading gauge. Furthermore, their axle load had been reduced to less than 24 tons what was still high for Australian standards, but not too high. With a driver diameter of six feet and three inches (1,905 mm) they could also be used for freight service if needed.

They were numbered 600 to 609. In 1934, 609 hauled the Royal Train and was named “Duke of Gloucester”. Between 1939 and 1942, all were rebuilt to class 600C. In this process they received new boilers with a pressure of 215 instead of 200 psi and 330 square feet of firebox heating surface instead of 270. Half of the ten locomotives were upgraded with automatic stokers, while the other half were converted to burn oil. Over time, they also got smoke deflectors. Withdrawals were between 1958 and 1961 and all were scrapped.