South Australian Railways 500 class (steam)

The South Australian Railways 500 class was a class of ten 4-8-2 steam locomotives built by Armstrong Whitworth in England and introduced in 1925, part of a larger order for 30 locomotives that the railways commissioner William Webb placed in 1924 to rehabilitate the South Australian rail system. They replaced the Rx and S class engines, many dating from 1894, which had forced double and even triple heading on main lines. All ten arrived in Adelaide in 1926 and worked the Adelaide to Wolseley line as far as Tailem Bend, each named after a notable South Australian. In 1928 locomotive 506 was fitted with a booster in a four-wheel trailing truck, raising tractive effort from 51,000 to 59,000 pounds-force, and boosters followed on the other nine, making the class the 500B with a 4-8-4 wheel arrangement and, for a time, the most powerful steam class in Australia. Most were semi-streamlined in the 1930s. The last was withdrawn in 1963, and 504 is preserved at the National Railway Museum in Port Adelaide.