Australian Standard Garratt

The Australian Standard Garratt (ASG) is a Garratt articulated steam locomotive designed and built in Australia during World War II for use on the 1067 mm (3 ft 6 in) narrow-gauge railway systems owned by the Australian states of Queensland, South Australia, Tasmania and Western Australia. After the war, ASGs operated in South Australia and at the Fyansford Cement Works railway in Victoria.

With the outbreak of World War II, in 1939 the federal government formed the Commonwealth Land Transport Board (CLTB) to take responsibility for the country's land transport networks. In the national interest it was empowered to over-ride decisions of the state railways. In 1942, the CLTB appointed the Commissioner of Railways in Western Australia, Joseph Ellis, to investigate the capacity of Australia's narrow gauge network and recommend what locomotives should be purchased. Ellis recommended that three variations of Garratt locomotive be purchased; heavy, medium and light.

The CLTB elected to build only the light type to allow it to operate on any narrow gauge line in Australia. After an attempt to obtain drawings and licences from Beyer, Peacock and Company failed, in July 1942 the CLTB recommended to the War Cabinet that 30 locomotives be built locally. In August 1942, the War Cabinet approved the order, which was increased to 65 locomotives in November 1942. The Western Australian Government Railways' Chief Mechanical Engineer Frederick Mills was seconded to lead a team of engineers in Melbourne to design the new locomotive. The Queensland Railways were vocal opponents, stating its preference for a modified version of its C17 class.

The result was the Australian Standard Garratt locomotive. The first was built in a record-breaking four months, entering service in September 1943. Only 57 ASGs were completed; assembly of the remaining eight was cancelled at the end of the war. The locomotives were built by the WAGR's Midland Railway Workshops (10), the Victorian Railways' Newport Workshops (12), the South Australian Railways' Islington Railway Workshops (13), and Clyde Engineering, Sydney (22).

Because of differences between the states, especially in regard to loading gauges, the sharpness of curves, and axle load, especially in Queensland, the design had to be a compromise, which went against the idea of having a standardised design.

To enable the long-wheelbase engine units to negotiate sharp curves, the 1st and 3rd driving wheels were designed to be flangeless, but this proved to be a major flaw as it led to a tendency for the locomotives to derail on curves and points. Another key problem, which made the ASGs unpopular with locomotive crews, was that the firebox door opened flat on the floor of the driving cab, maximising heat radiation into the crew compartment. This resulted in them having fairly short lives with most withdrawn by the mid-1950s. Some were resold for use on the Emu Bay and Fyansford Cement Works Railways where they would have more successful careers.

The Queensland Railways purchased 23. One was never used and another saw only two months service. In September 1945, the drivers' union placed a ban on them. Attempts to modify them proved unsuccessful, and they were written off in 1948. Three were sold to the Emu Bay Railway and six to the Tasmanian Government Railways, with the remainder scrapped in 1954/55.

The Tasmanian Government Railways purchased 14 new and another six second-hand from the Queensland Railways. Two were sold to the Emu Bay Railway with the remainder scrapped in the late 1950s.