South Australian Railways 520 class

South Australian Railways 520 class

Preserved 520 Sir Malcolm Barclay Harvey at Mount Gambier station in May 1984

Type and origin Power type Steam Designer Frank Hugh Harrison Builder Islington Railway Workshops Serial number 81-92 Build date 1943-1947 Total produced 12

Specifications Configuration 4-8-4 Gauge 1,600 mm (5 ft 3 in) Driver dia. 5 ft 6 in (1.676 m) Length 87 ft 4 in (26.62 m) Axle load 15 long tons 16 cwt (35,400 lb or 16.1 t) Adhesive weight 62 long tons 10 cwt (140,000 lb or 63.5 t) Loco weight 111 long tons 8 cwt (249,500 lb or 113.2 t) Total weight 200 long tons 13 cwt (449,500 lb or 203.9 t) Fuel type Coal Fuel capacity 9 long tons 15 cwt (21,800 lb or 9.9 t) Water cap 9,100 imp gal (41,000 l; 10,900 US gal) Firebox:  • Firegrate area 45 sq ft (4.2 m2) Boiler pressure 215 psi (1,482 kPa) Heating surface:  • Tubes 2,163 sq ft (200.9 m2)  • Firebox 291 sq ft (27.0 m2) Cylinders 2 Cylinder size 20.5 in × 28 in (521 mm × 711 mm) Valve gear Walschaerts

Performance figures Tractive effort 32,600 lbf (145 kN)

Career Operators South Australian Railways Numbers 520-531 Nicknames Whispering Giants Preserved 520, 523 Scrapped 1961-1971 Disposition 2 preserved, 10 scrapped

The South Australian Railways 520 class was a class of 4-8-4 steam locomotives operated by the South Australian Railways.

During the war years in the early 1940s, the South Australian Railways (SAR) had a desperate need for additional tractive power on increasingly growing troop and supply trains and with the combined need for quick acceleration and high speed running on the flat and general straight mainlines to the north to Port Pirie, as well as power "under the belt" for the long 19-mile (31 km), 1-in-45 (2.2%) graded slog up the Adelaide Hills to Melbourne, a new locomotive design was required by the SAR. With this in mind, the 520 class was commissioned, combining the better features of the earlier 500 and 620 class locomotives.

The class used the 4-8-4 configuration of the modified 500B class, but was also designed for work on branch lines with light 60-lb/yard (29.7 kg/m) rail with a reduced tender load. The considerable weight of the locomotive was spread over eight axles, four driving and four in the leading and trailing trucks, yielding the necessary light axle loading for operation over the aforementioned territory. The 520s used this to the fullest, their normal mainline stamping grounds being on fast crack express services on the Pirie line, namely the East-West Express, but also serving upon many of the Tailem Bend mixed and radiating branchline trains. The only lines that they were restricted from running on were those laid with very light 40 lb or 50 lb rail.

The class featured extravagant streamlining, in the style of the Pennsylvania Railroad's T1 in the United States. The original streamlining was more closely based on the T1, and class members 520-522 were fitted with such. Members 523-531 were built with a narrower front profile, attributed to by the "crown" of grill around the chimney front. The earlier streamlined model had a lower front, resulting in a squat chimney profile extended from an otherwise graceful, albeit useless, streamlined casing. During their service life, some of the class lost the cowling around their front buffer beam, a move which simplified maintenance.