British Rail Class 73

British Rail Class 73
Class 73, no. 73201 at Woking. This locomotive was used by South West Trains as a “Thunderbird” to rescue failed trains.
Type and origin Power type Electro-diesel Builder 73/0: British Railways’ Eastleigh Works 73/1: English Electric at Vulcan Foundry Build date 1962, 1965–1967 Total produced 49
Specifications Configuration: ​  • Whyte Bo-Bo  • UIC Bo'Bo' Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 3 ft 4 in (1.016 m) Length 16.36 m (53 ft 8 in) Loco weight 73/0: 76.30 long tons (77.52 t) 73/1: 76.80 long tons (78.03 t) Electric system/s 660–750 V DC Current pickup(s) Third rail Prime mover English Electric 4SRKT Mk II Traction motors 73/0: EE 542A 73/1: EE 546/1B Train heating Electric Train Heating Train brakes Vacuum, Air and Electro-Pneumatic
Performance figures Top speed 73/0: 80 mph (129 km/h) 73/1: 90 mph (145 km/h) Power output Electric (continuous): 1,420 hp (1,059 kW) Electric (one-hour): 1,600 hp (1,193 kW) Engine: 600 hp (447 kW) Tractive effort 73/0 (electric): 42,000 lbf (186.8 kN) 73/0 (diesel): 34,100 lbf (151.7 kN) 71/0 (electric): 40,000 lbf (177.9 kN) 73/1 (diesel): 36,000 lbf (160.1 kN)
Career Railroad(s) British Rail Eurostar FM Rail Gatwick Express FirstGBRf Network Rail South West Trains Number E6001–E6049; later 73001–73006, 73101–73142 Axle load class Route availability 6

Class 73, no. E6013 (73107) at Rowsley South, on the Peak Railway on 17 April 2003. This locomotive was on loan from Fragonset Railways, and has since returned to main-line service.

Class 73/1 73101 in BR blue livery

The British Rail Class 73 electro-diesel locomotives are very unusual in that they can operate from a 750 V DC third-rail supply but also have a diesel engine to allow them to operate on non-electrified routes. This makes them very versatile, although the diesel engine produces less power than is available from the third-rail supply so they rarely stray from the former Southern Region of British Rail. Following the withdrawal of the more powerful Class 74 electro-diesels in 1977, the Class 73 is now unique on the British rail system.