Tom Barr Smith
South Australian Railways - Broad Gauge

Class operators South Australian Railways
Condition Excellent
Ownership History Trust of South Australia
Provenance South Australian Railways
Class Builders Sir W. G. Armstrong-Whitworth & Co., Newcastle-on-Tyne, England
Number in class 10
Number series 500 - 509
Designer F. J. Shea
Entered service 18th October 1926
Condemmed 9th July 1962
Entered the museum 23rd July 1965
Length (over coupling points) 84´ 2
Total Weight 222 tons 6 cwt (225,856 kilograms)
Tractive Effort 59,000 lbs
Wheel Arrangement 4-8-4 (4-8-2 original)
Driving Wheels Diameter 63
Maximum Axle Load 22 tons 3 cwt (22,504 kilograms)
Boiler Pressure 200 lbs psi
Cylinders 2x outside 26
Valve Gear Walschaert
Water Capacity 7,000 gallons (31,822 litres)
Coal Capacity 11 tons (11,176 kilograms)
Grate Area 66.6 sq ft
Mileage 855,029 miles (1,375,998 kilometres)
Maximum Speed 50 mph (80 km/h)
Built by Sir W. G. Armstrong-Whitworth & Co., Newcastle-on-Tyne, England

From the mid-1880s, when the South Australian Railways Nairne Railway (later to become the first section of the Main South Line) began its push southward from Adelaide, the Mt. Lofty Ranges posed immediate problems for the construction and mechanical engineers of the day. The rails had to climb 1534 feet (468 metres) in 19.4 miles (31.4 kilometres) and pass through eight tunnels to reach the summit at Mt. Lofty, and locomotives of sufficient power to conquer the 1 in 45 grades designed and built.

The four Baldwin built locomotives ordered for this purpose were soon found to be unsuited, and the small K-class 0-6-4Ts, usually working in pairs, were forced to handle the traffic for a while. The first of the R-class arrived in 1886 and, later re-built to the more powerful Rx-class, they worked all major South Line trains until the 1920s. As traffic increased these engines had also to be worked in pairs with, sometimes, a third pushing in the rear. Around 1920 a half-hearted attempt was made at designing a more powerful locomotive, but it was left to the Webb administration to solve the problem.

W. A. (Bill) Webb had come from the Missouri-Kansas-Texas Railroad to rehabilitate an ailing SAR, and one of his first tasks was to upgrade its motive powere. This job was given to his Chief Mechanical Engineer, Fred Shea, who set about designing three classes of very powerful locomotives, the like of which had not before been seen in South Australia. They were the 500, 600 and 700 classes.

The 500-class 4-8-2 was a machine of magnificent size and power and was to immediately capture the imaginations of South Australians. At 213 tons and exerting a tractive effort of 51,000 lbs, it was almost two-and-a-half times more powerful than the Rx-class. Whereas an Rx unaided could haul 190 tons over Mt. Lofty, the 500s could lift 400 tons - later increased to 450 tons.

In a constant quest for more power it was decided to equip the 500s with boosters (small auxillary steam engines). This necessitated the replacement of the two-wheel trailing truck with one of four wheels. The booster contributed an extra 8,000 lbs to the tractive effort and permitted an increase in the engine load over Mt. Lofty to 540 tons. The 500s were now 4-8-4s and were reclassified 500B. No.504 was modified and reissued to traffic on 23rd August 1929.

During the 1930s the 500s underwent yet another change in appearance when they were semi streamlined after the style of the Southern Pacific´s (USA) GS-2 class "Daylights", and with their silvered smokebox doors they soon became known as "Palefaces". Perhaps they are remembered most for providing the head-end power for The Overland between Adelaide and Tailem Bend for thirty years. They were permitted a maximum load of eleven E-class Joint Stock cars, and the sight and sound of them blasting upgrade presented a truly magnificent spectacle. In addition, together with the 720B-class 2-8-4s, they hauled most south line freight trains with occasional turns on the Terowie and Port Pirie lines.

With the introduction of the 900-class diesel electrics in the early 1950s the 500Bs began to relinquish their exalted status and by the early ´60s only Nos.500 and 504 remained avail-able for traffic. Both were used for a time on ARHS excursions, but 504 was earmarked for preservation. It was written off and placed in the Mile End Railway Museum on 23 July 1965.