The South Australian Railways 500 class was a class of 4-8-2

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, Fuel oil, oil or, rarely, Wood fuel, wood) to heat ...

s operated by the

South Australian Railways South Australian Railways (SAR) was the organisation through which the Government of South Australia built and operated railways in South Australia from 1854 until March 1978, when its non-urban railways were incorporated into Australian Natio ...

. The locomotives were rebuilt in 1928, when

booster engine A locomotive booster for steam locomotives is a small supplementary two-cylinder steam engine back-gear-connected to the trailing truck axle on the locomotive or one of the trucks on the tender. It was invented in 1918 by Howard L. Ingersoll, ...

s were installed, becoming the 500B class with a wheel arrangement of

4-8-4 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type wa ...

and a tractive effort of . The 500B class were the second-most-powerful non-articulated steam locomotives to operate in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, behind the NSWGR D57 4-8-2.

History

The 500 class were part of larger order for 30 steam locomotives placed with

Armstrong Whitworth Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. With headquarters in Elswick, Tyne and Wear, Elswick, Newcastle upon Tyne, Armstrong Whitworth built armaments, ships, locomot ...

, England, in 1924, as part of the rehabilitation of the state's rail system being overseen by Railways Commissioner William Webb. They replaced the Rx and S class locomotives, many dating back to 1894, that were still performing mainline duties, meaning that double and even triple heading was common. All ten 500-class locomotives arrived in

Adelaide Adelaide ( , ; ) is the list of Australian capital cities, capital and most populous city of South Australia, as well as the list of cities in Australia by population, fifth-most populous city in Australia. The name "Adelaide" may refer to ei ...

in 1926, and entered service on the Adelaide to Wolseley line as far as

Tailem Bend Tailem Bend (locally, "Tailem") is a rural town in South Australia, south-east of the state capital of Adelaide. It is located on the lower reaches of the River Murray, near where the river flows into Lake Alexandrina (South Australia), Lake Al ...

. All were named after notable South Australians.

Rebuilding

In May 1928, 506 was experimentally fitted with a

booster Booster may refer to: Amusement rides * Booster (Fabbri ride), a pendulum ride * Booster (HUSS ride), an evolution of the Breakdance ride * Booster (KMG ride), a pendulum ride Arts, entertainment, and media Fictional characters * Booster, a cha ...

in a newly built four-wheel

trailing truck On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (Wheelset (rail transport), wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing Bogie, t ...

, replacing the original unpowered two-wheel truck. The modification, popular in the United States, proved highly successful, increasing the locomotive's tractive effort from to . Boosters were subsequently fitted to the nine remaining locomotives, resulting in the class changing to 500B – although their popular name, among railway employees and the public alike, remained "

Mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

class" rather than their new " Northern" configuration. With their upgraded tractive effort, the 500B class briefly became the most powerful non-articulated

s to operate in

until supplanted the following year by the New South Wales D57 class. Throughout the mid-1930s, all but two of the locomotives in the class were semi-streamlined and had valances fitted. The first two locomotives were withdrawn from service in 1955 and the last was withdrawn in 1963. 504 is preserved as a static exhibit at the National Railway Museum, Port Adelaide.

History

Rebuilding

Class list

References

Further reading