British Rail Class 20

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English Electric Type 1
British Rail Class 20
Hunslet-Barclay 20903 on a weedkilling train at Doncaster, April 1994
Power type Diesel-electric
Builder English Electric at Vulcan Foundry and Robert Stephenson and Hawthorns
Build date 1957–1962, 1966–1968
Configuration Bo-Bo
UIC classification Bo'Bo'
Gauge ft 8+12 in (1,435 mmstandard gauge
Wheel diameter 3 ft 7 in (1.092 m)
Minimum curve 3.5 chains (70 m)
Wheelbase 32 ft 6 in (9.91 m)
Length 46 ft 9 12 in (14.262 m)
Width 8 ft 9 in (2.67 m)
Height 12 ft 8 in (3.86 m)
Locomotive weight 72 long tons (73.2 t)
Fuel capacity 380 imp gal (1,700 l; 460 US gal)
Prime mover English Electric 8 SVT Mk.II
Traction motors D8000–D8049: EE 526/5D
Remainder: EE 526/8D
Transmission DC generator, DC traction motors
Multiple working Blue Star
Top speed 75 mph (121 km/h)
Power output Engine: 1,000 hp (746 kW)
Tractive effort Maximum: 42,000 lbf (186.8 kN)
Train heating None
Locomotive brakeforce 35 long tons-force (349 kN)
Train brakes Vacuum
Career British Railways
Number D8000–D8199, D8300–D8327; later 20001–20228
Axle load class Route availability 5

The British Rail Class 20, also known as an English Electric Type 1, is a class of diesel electric locomotive. 228 locomotives in the class were built by English Electric between 1957 and 1968. The large number was partly to do with the failure of other early designs in the same power range, and reliable locomotives being needed.

The locomotives were originally numbered D8000–D8199 and D8300–D8327. They are known by railway enthusiasts as "Choppers"[1][2], a name taken from the distinctive beat the engine produces under load which resembles the sound of a helicopter.

References[change | edit source]

  1. Oakley, Michael (1981). BR Class 20 diesels. Truro: Bradford Barton / D&EG. ISBN 0 85153 419 8.
  2. "'At least 20 20s' for Barrow Hill diesel jubilee". The Railway Magazine: page 9. July 2007.