4-8-4 Steam Locomotives in Australia

Class 500B class (Locobase 2419)

Data from [] . See also Rob Burford, "The 500 Class of the South Australian Railways," Modeling the Railways of South Australia 2007, pp. 4-123 to 4-138. See also Allen Hazen's comments in a Railroad.Net thread he began on 6 December 2011 asking for "Comparative 4-8-4 data ...please?" at [], last accessed 14 April 2017; data refinement came in his 30 April 2012 and 1 May 2012 posts containing specifications. Works numbers were 633-642.

One of the largest locomotives operated in Australia, these mixed-traffic engines were designed by FJ Shea. Although built in England, the bar frames were subcontracted from Baldwin. Although delivered as Mountains (4-8-2), they became Northerns beginning in 1929 to accommodate a booster that supplied 8,000 lb (3,629 kg) of tractive effort on starting; the last of these -- 503 and 508 -- weren't altered until 1936. Performance included scaling the 2.2% Mount Lofty incline with 550 tons at 15 mph with the booster cut in.

When dieselization came to the main line, these engines were out of a job as they were too heavy for branch line service.

All left service between 1958 and 1962. [] has the details on the class, including its impressive total mileage. The lowest was 502's 836,000 miles, the champ was 501's 1,029,926.

Class 520 Class (Locobase 1131)

Data from H. Le Fleming in Ransome-Wallis - 1959; and South Australian Railways 1943 diagram signed by F H Harrison See also Brian Hollingsworth (1982), the museum-railway site [] (visited 20 October 2003), "The 520 Class 4-8-4 Locomotive-South Australian Government Railways", ARHS Bulletin (March 1944),pp. pages 31-32; and "The SAR 520 Class Locomotive", Catchpoint (March 1993), pp. 12-16 , archived on "Steam Ranger Heritage", part of the Steam Ranger website

This was essentially a branch-line 4-8-4 that had so many axles, Hollingsworth (1982) points out, because it had to travel on 60-lb/yard (30 kg/m) rail. Designed by SAR's PH Harrison, the locomotive wore a streamline casing very similar to that of the Pennsylvania's T-1 (Locobase 348). 520s had roller bearings on all axles and pulled 675-ton trains at 70 mph (113 kph) (which suggests 2,600 IHP). The steamranger account notes that the first engine, 520, entered service with the S.A.R. on 10 November, 1943 on the Port Pirie line achieving a maximum speed of 78 mph (126 kph) between Red Hill and Port Pirie.

Other features included 12"(305 mm) piston valves and a Belpaire firebox with two thermic syphons. Tender weight varied. On 80-lb rail (40 kg/m), it was as shown in the specifications. On 60-lb rail, the tender carried less water (8,200 Imp gal, 9,840 US gal), 5 long tons (5.5 short tons or 5,588 kg) and weighed 180,544 lb (81,893 kg).

Steamranger's verdict" "The 520s were a very successful engine, so much so that they were the last of the "big" steam engines to remain in service when dieselisation came."

All twelve engines were converted to coal-oil (i.e., a mixture of the two) burning in 1948. They served until the early sixties.