The reference for locomotives and railcars
British Rail class 42
originally D800
Great Britain | 1958 | 38 produced
D829 Magpie in October 1961 with an express train bound for Plymouth at London-Paddington
D829 Magpie in October 1961 with an express train bound for Plymouth at London-Paddington
Ben Brooksbank

For the mountainous routes in Devon and Cornwall, the Western Region decided to purchase lighter diesel-hydraulic locomotives. Since Germany was the leader in this area, the technology of the V 200 of the Bundesbahn was licensed and packed into the smaller loading gauge. The resulting D800 (later class 42 or “Warship class”) was built in Swindon and had two Maybach engines built at Bristol Siddeley, each mated to a Mekydro gearbox. At the same time, the Class 43 was developed at North British with MAN engines and Voith transmissions. Since those responsible had an aversion to diesel-hydraulic locomotives, both classes were retired by 1972.

Axle configB-B 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length60 ft 0 in
Wheelbase48 ft 3 in
Service weight174,720 lbs
Adhesive weight174,720 lbs
Axle load43,680 lbs
Power sourcediesel-hydraulic
Top speed90 mph
Starting effort48,200 lbf
EngineBristol Siddeley (Maybach) MD650
Engine type2x V12 diesel
Fuel960 us gal (diesel)
Engine output2,070 hp (1,544 kW)2,270 hp (1,693 kW)
Power Plant
Calculated Values
diesel locomotive
last changed: 07/2023

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