South Australian Railways 620 class

South Australian Railways 620 class

The preserved example of the 620 class, the SteamRanger 621 Duke of Edinburgh.
Type and origin
Power type Steam
Designer P. J. Shea
Builder South Australian Railways, Islington Railway Workshops
Build date 1936–1938
Total produced 10
Specifications
Configuration 4-6-2
UIC class 2′C1′h
Gauge 5 ft 3 in (1,600 mm)
Driver diameter 5 ft 6 in (1.676 m)
Length 69 ft 8 in (21.23 m)
Axle load 15 long tons 18 cwt (35,600 lb or 16.2 t)
Adhesive weight 47 long tons 5 cwt (105,800 lb or 48 t)
Loco weight 81 long tons 10 cwt (182,600 lb or 82.8 t)
Loco & tender weight 140 long tons 15 cwt (315,300 lb or 143 t)
Fuel type Coal
Fuel capacity 9 long tons 0 cwt (20,200 lb or 9.1 t)
Water cap 5,200 imp gal (24,000 l)
Firebox:
 • Firegrate area		 33.4 sq ft (3.10 m2)
Boiler pressure 200 psi (1,379 kPa)
Heating surface:
 • Tubes		 1,560 sq ft (145 m2)
 • Firebox 175 sq ft (16.3 m2)
Superheater:
 • Heating area		 421 sq ft (39.1 m2)
Cylinders Two
Cylinder size 18.5 in × 28 in (470 mm × 711 mm)
Valve gear Baker
Performance figures
Tractive effort 25,239 lbf (112.27 kN)
Career
Operators South Australian Railways
Class 620
Numbers 620–629
Preserved 621, 624
Scrapped 1964–1969
Disposition Two preserved, eight scrapped

The South Australian Railways 620 class is a class of 10 4-6-2 Pacific steam locomotives built in the late 1930s, designed to operate on lightly laid 60-pound lines.

Development of the 620class

The completion of the South Australian Railways (SAR) broad gauge route between Adelaide and Port Pirie created a need for a fast, light passenger locomotive to haul this service, as well as other traffic on the lightly laid 60 lb/yd (29.8 kg/m) rail branch lines of the SAR. The specification included the ability to haul a 200-long-ton (200 t; 220-short-ton) train up a 1-in-45 (2.2%) grade at 25 miles per hour (40 km/h).

Mr P.J. Shea, Chief Mechanical Engineer of the SAR designed a 140-ton Pacific type. A notable feature of the design, unique to South Australian Railways,[1] was the use of Baker valve gear in lieu of the more common Walschaerts valve gear.[2] The first locomotive (620) was completed at the SAR workshops at the Islington Railway Workshops in 1936, with the tenth and final locomotive of the class (629) completed in 1938.

Class leader No. 620 was also notable for being Australia's first streamlined locomotive, the smokebox being covered with a chromed steel grille similar to those fitted to motor cars of the period, and painted Hawthorn green with yellow stripes.[1] The press of the time described 620's appearance as 'a bit of fluff'. The remainder of the class were unstreamlined.

In service, the 620 class replaced the Q and S 4-4-0 types 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 passenger services, as well as continued service on Mallee 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.[2]

In 1994, the 'Duke of Edinburgh' steam locomotive number 621 ran a one-off special steam hauled tour into Victoria just before the Melbourne to Adelaide mainline was converted from broad gauge rail line to a standard gauge track. This was the first ever time a South Australian Railways steam locomotive had ever 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 in Victoria, due to the locomotive being too wide for the stations situated along the Melbourne suburban railway system. The locomotive combined with Victorian Railways R Class Steam locomotive 761 for the majority of the tour from Wolseley in South Australia to Bacchus Marsh in Victoria.

All but two of the locomotives were scrapped by 1969. One is preserved in working condition by SteamRanger (621) with the second (624) held in the National Railway Museum, Port Adelaide.

Stocklist

Engine Number Builder Date in Service Date Condemned Name
620 Islington Railway Workshops 26/06/1936 July 1961 Sir Winston Dugan
621 Islington Railway Workshops 07/09/1936 Preserved in Service Duke of Edinburgh
622 Islington Railway Workshops 07/10/1936 February 1969 -
623 Islington Railway Workshops 21/07/1937 July 1964 -
624 Islington Railway Workshops 17/07/1937 Static Display -
625 Islington Railway Workshops 24/08/1937 June 1968 -
626 Islington Railway Workshops 08/10/1937 February 1969 -
627 Islington Railway Workshops 26/11/1937 February 1969 -
628 Islington Railway Workshops 20/12/1937 June 1968 -
629 Islington Railway Workshops 22/03/1938 February 1969 -

Gallery

References

Specific

  1. 1 2 "National Railway Museum - Port Adelaide (620-class 4-6-2 locomotive No.624)". www.nationalrailmuseum.org.au. Retrieved 2007-06-18.
  2. 1 2 "SteamRanger Enthusiast Page - Steam Locos". www.steamranger.org.au. Retrieved 2007-06-18.

External links

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