South Australian Railways 500 class (steam)

South Australian Railways 500 class
South Australian Railways 500B class locomotive no. 504 "Tom Barr Smith", newly streamlined, about 1937
Type and origin Power type Steam Designer USRA Light Mikado modified by Fred Shea Builder Armstrong Whitworth Serial number 633-642 Build date 1925 Total produced 10 Rebuilder Islington Railway Workshops Rebuild date 1929-1936 Number rebuilt 10
Specifications Configuration: ​  • Whyte As built: 4-8-2 2'D1' 2'2′ With booster:4-8-4 2'D2' 2'2' Gauge 5 ft 3 in (1,600 mm) Leading dia. 33 in (838 mm) Driver dia. 63 in (1,600 mm) Trailing dia. 36 in (914 mm) 42 in (1,067 mm) Length 83 ft 11 in (25,578 mm) (as built) 84 ft 2 in (25,654 mm) (rebuilt) Height 13 ft 11+1⁄2 in (4,254.5 mm) Axle load 22 long tons 7 hundredweight 2 quarters (25.06 short tons; 22.73 t) (as built) 222 long tons 3 hundredweight (24.8 short tons; 22.5 t) (rebuilt) Adhesive weight 88.85 long tons (99.51 short tons; 90.28 t) (as built) 87.20 long tons (97.66 short tons; 88.60 t) (rebuilt) Loco weight 135.80 long tons (152.10 short tons; 137.98 t) (as built) 143.80 long tons (161.06 short tons; 146.11 t) (rebuilt) Tender weight 85.15 long tons (95.37 short tons; 86.52 t) (as built) 78.80 long tons (88.26 short tons; 80.06 t) (rebuilt) Total weight 218 long tons 13 hundredweight (244.9 short tons; 222.2 t) (as built) 222 long tons 6 hundredweight (249.0 short tons; 225.9 t) (rebuilt) Fuel type Coal Fuel capacity 12 long tons (13 short tons; 12 t) (as built) 11 long tons (12 short tons; 11 t) (rebuilt) Water cap. 8,300 imperial gallons (10,000 US gal; 38,000 L) as built (Water capacity reduced to 7,100 imperial gallons (8,500 US gal; 32,000 L) in 1930) 7,000 imperial gallons (8,400 US gal; 32,000 L) (rebuilt) Firebox: ​  • Grate area 66.6 sq ft (6.19 m2) Boiler pressure 200 psi (1,379 kPa) Heating surface: ​  • Firebox 395 sq ft (36.7 m2)  • Tubes and flues 3,253 sq ft (302.2 m2) Superheater: ​  • Heating area 835 sq ft (77.6 m2) Cylinders 2 Cylinder size 26 in × 28 in (660 mm × 711 mm) Valve gear Walschaerts valve gear Valve type Piston
Performance figures Tractive effort 51,000 lb (23,000 kg) (as built) 59,000 lb (27,000 kg) (rebuilt) Factor of adh. 4
Career Operators South Australian Railways Class 500 Number in class 10 Numbers 500-509 First run 22/5/1926 Last run 11/5/1963 Withdrawn 1958-1963 Preserved 504 Scrapped 1961-1965 Disposition 1 preserved, 9 scrapped

The South Australian Railways 500 class was a class of 4-8-2 steam locomotives operated by the South Australian Railways. The locomotives were rebuilt in 1928, when booster engines were installed, becoming the 500B class with a wheel arrangement of 4-8-4 and a tractive effort of 59,000 pounds-force (260 kN). The 500B class were the second-most-powerful non-articulated steam locomotives to operate in Australia, behind the NSWGR D57 4-8-2.

The 500 class were part of larger order for 30 steam locomotives placed with Armstrong Whitworth, 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 in 1926, and entered service on the Adelaide to Wolseley line as far as Tailem Bend. All were named after notable South Australians.^[1]

In May 1928, 506 was experimentally fitted with a booster in a newly built four-wheel trailing truck, replacing the original unpowered two-wheel truck. The modification, popular in the United States, proved highly successful, increasing the locomotive's tractive effort from 51,000 pounds-force (230 kN) to 59,000 pounds-force (260 kN). 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 class" rather than their new "Northern" configuration. With their upgraded tractive effort, the 500B class briefly became the most powerful non-articulated steam locomotives to operate in Australia^{[2][user-generated source]} 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 1962.^[1]

504 is preserved as a static exhibit at the National Railway Museum, Port Adelaide.^[3]

• Douglas Colquhoun; Ronald Stewien; Adrian Thomas (1969). 500 The 4-8-2 and 4-8-4 Locomotives of The South Australian Railways. Australian Railway Historical Society, SA.
• David Burke (2000). Giants of Steam. Australian Railway Historical Society, NSW.
• Leon Oberg (2007). Locomotives of Australia. Rosenberg Publishing, NSW.
• Ron Stewien (2011). A History of the South Australian Railways, Volume 5: Controversy and Mr Webb. Eveleigh Press, NSW.
• Ron Stewien (2010). A History of the South Australian Railways, Volume 6: Mountains, Mikados and Pacifics. Eveleigh Press, NSW.
• Drymalik, Chris. "Broad Gauge 500-class 4-8-2 (later 500B-class 4-8-4) locomotives". comrails.com. Retrieved 19 March 2013.