Victorian Railways S class

Victorian Railways S class
Builder's photo of S300, 1928
Type and origin Power type Steam Builder Newport Workshops Build date 1928 Total produced 4
Specifications Configuration: ​  • Whyte 4-6-2 Gauge 1,600 mm (5 ft 3 in) Driver dia. 72 15⁄16 in (1,853 mm) Length 1928: 78 ft 6 3⁄4 in (23.95 m) 1951: 85 ft 6 in (26.06 m) Axle load 23 LT 10 cwt (23.9 t) Adhesive weight 70 LT 10 cwt (71.6 t) Loco weight 1928: 112 LT 5 cwt (114.05 t) 1951: 114 LT 10 c (116.3 t) Tender weight 1928: 82 LT 8 cwt (83.7 t) 1951: 109 LT 7 c (111.10 t) Total weight 1928: 194 LT 13 cwt (197.77 t) 1951: 223 LT 17 cwt (227.44 t) Fuel type Coal Oil Fuel capacity 1928: 9 long tons (9 t) 1951: 2,000 imp gal (9,092 L; 2,402 US gal) Water cap 1928: 8,600 imp gal (39,096 L; 10,328 US gal) 1951: 12,600 imp gal (57,281 L; 15,132 US gal) water Firebox:  • Firegrate area 50 sq ft (4.6 m2) Boiler pressure 200 psi (1.38 MPa) Heating surface 1928: 3,691 sq ft (342.9 m2) 1951: 3,723 sq ft (345.9 m2) Superheater: ​  • Heating area 570 sq ft (53.0 m2) Cylinders 3 Cylinder size 20.5 in × 28 in (521 mm × 711 mm) Valve gear Walschaerts/Gresley Valve type 10-inch (254 mm) piston valves Valve travel 6 inches (152 mm) Valve lap 1 1⁄4 inches (32 mm); exhaust lap: −3⁄16 inch (−4.8 mm) Valve lead 5⁄16 inch (7.9 mm)
Performance figures Power output at drawbar: 2,300 horsepower (1,720 kW) at 45 miles per hour (72 km/h) Tractive effort 41,670 lbf (185.4 kN) at 85% boiler pressure
Career Operators Victorian Railways Numbers S300-S303 Delivered 1928-30 Disposition all scrapped

The Victorian Railways S class was a class of 4-6-2 express passenger steam locomotive operated by the Victorian Railways (VR) in Australia between 1928 and 1954. Built when the VR was at its zenith and assigned to haul the broad gauge-leg of its Melbourne to Sydney interstate express passenger services, the S class remained the VR's most prestigious locomotive class until the advent of diesel electric locomotives in the early 1950s.

They were the first Pacific-type locomotives on the VR, as well as its first 3-cylinder locomotive type. Renowned for their power and speed, in the ten years that followed their introduction the running time of the premier Sydney express service they operated was progressively reduced by one and a half hours. These service improvements culminated in 1937 with the replacement of the Sydney Limited with the Art Deco streamliner Spirit of Progress, and the S class locomotives were fitted with streamlined casings to match the new train set. They were also equipped with long-range tenders to enable the entire 190 ¹⁄₂-mile (306.6 km) journey to be run non-stop at a speed that remained for the next 20 years Australia's fastest train service.

Although only four S class locomotives were built, they were highly utilised. They ran up annual mileages double that of other classes of locomotives on the VR and by 1954 had run a combined total of approximately 5,700,000 miles (9,200,000 km). However their size and heavy axle load made them unsuitable for regular service on any other lines than the North Eastern line, and so within six months of the introduction of the new B class diesel locomotives on the Spirit of Progress roster in April 1954 the S class had all been withdrawn and scrapped. Their scrapping was a catalyst for the rail preservation movement in Victoria to lobby for the preservation of remaining examples of other VR steam locomotives, resulting in the establishment in 1962 of the Australian Railway Historical Society Museum in Williamstown North.