The South Australian Railways 620 class was a class of

4-6-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, six powered and coupled driving wheels on three axles and two trailing wheels on one axle. The locomoti ...

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 ...

History

The completion of the South Australian Railway (SAR)

broad gauge A broad-gauge railway is a railway with a track gauge (the distance between the rails) broader than the used by standard-gauge railways. Broad gauge of , more known as Russian gauge, is the dominant track gauge in former Soviet Union countries ...

route between

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 ...

and

Port Pirie Port Pirie is a small city on the east coast of the Spencer Gulf in South Australia, north of the state capital, Adelaide. Port Pirie is the largest city and the main retail centre of the Mid North region of South Australia. The city has an ex ...

created a need for a fast, light passenger locomotive to haul this service, as well as other traffic on the lightly laid rail branch lines of the SAR. The specification included the ability to haul a train up a 1-in-45 (2.2%) grade at . Fred Shea, Chief Mechanical Engineer of the SAR designed a Pacific type. A notable feature of the design, unique to South Australian Railways, was the use of

Baker valve gear After about 1910, the Baker valve gear was the main competitor to Walschaerts valve gear for steam locomotives in the United States. Strictly speaking it was not a valve gear but a variable expansion mechanism adapted to the Walschaerts layout repl ...

in lieu of the more common

Walschaerts valve gear The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgium, Belgian railway mechanical engineering, engineer Egide Walschaerts in 1844. The gear is sometimes name ...

. The first locomotive was completed at the

Islington Railway Workshops The Islington Railway Workshops are railway workshops in the northern suburbs of Adelaide, South Australia. They were the chief railway workshops of the South Australian Railways, and are still in operation today.Class leader The lead ship, name ship, or class leader is the first of a series or class of ships that are all constructed according to the same general design. The term is applicable to naval ships and large civilian vessels. Large ships are very complex ...

620 was also notable for being Australia's first

streamlined Streamlines, streaklines and pathlines are field lines in a fluid flow. They differ only when the flow changes with time, that is, when the flow is not steady flow, steady. Considering a velocity vector field in three-dimensional space in the f ...

locomotive, the smokebox being covered with a chromed steel grille similar to those fitted to motor cars of the period, painted in resplendent Hawthorn Green and Silver. The press of the time described 620's appearance as 'a bit of fluff'. The remainder of the class was unstreamlined. In service, the 620 class replaced the Q and S classes on branchline services, where they proved quite successful. With the introduction of the more powerful and modern 520 class from 1943, these locomotives were relegated to the Willunga, Bridgewater and

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 ...

passenger services, as well as continued service on

Murray Mallee The Murray Mallee is a cereal, grain-growing and sheep-farming area in the east of the Australian state of South Australia. The name is not formally designated but is widely used to refer to an area of approximately bounded by the Murray Rive ...

line services (the locomotives' light axle loading providing good route ability plus the "get up and go" characteristics common to large wheeled Pacific type locomotives. The 620 class was phased out in favour of Bluebird railcars, although a spate of railcar failures in 1954–55 saw the 620 class return to service on the Port Pirie line. All were withdrawn between 1964 and 1969.

Preservation

Two have been preserved: *621 by SteamRanger *624 by the

National Railway Museum, Port Adelaide The National Railway Museum, Port Adelaide, South Australia is the largest under-cover railway museum in Australia. More than 100 major exhibits, mainly from the South Australian Railways (SAR) and Commonwealth Railways and their successor, ...

624
National Railway Museum In 1994, 621 ran a one-off steam hauled tour into

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

shortly before the Adelaide to Melbourne line was converted from broad gauge to a standard gauge. This was the first and only time a South Australian Railways steam locomotive had worked east into Victoria and with the gauge conversion imminent, the tour would also be the last. The train travelled as far east as

Bacchus Marsh Bacchus Marsh ( Wathawurrung: ''Pullerbopulloke'') is a town in Victoria, Australia, located approximately north-west of the state capital Melbourne, at a near equidistance to the major cities of Melbourne, Ballarat and Geelong. As of the ...

, due to the locomotive being too wide for the stations situated along the Melbourne suburban railway system. The locomotive combined with R761 for the majority of the tour from Wolseley in South Australia to Bacchus Marsh in Victoria.

Class list

References

* * *

Specific

External links

*
South Australian Railways
(SAR) promotional photograph of streamlined locomotive 620 ''Sir Winston Duggan''
State Library of South Australia
photograph of streamlined locomotive 620 ''Sir Winston Duggan'' travelling through the

Mount Lofty Ranges The Mount Lofty Ranges are a range of mountains in the Australian state of South Australia which for a small part of its length borders the east of Adelaide. The part of the range in the vicinity of Adelaide is called the Adelaide Hills and d ...

, South Australia
620class:SA:Trains:AJH
Photographs and further details of the 620 class courtesy John Hurst {{South Australian Railways locos, state=expanded Railway locomotives introduced in 1936 620 class 4-6-2 locomotives 2′C1′ h2 locomotives Islington Railway Workshops locomotives Broad gauge locomotives in Australia Streamlined steam locomotives Passenger locomotives