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British Rail class 43 (High Speed Train)
originally classes 253 and 254
Great Britain | 1975 | 98 produced
HST in Intercity blue and gray livery at Slittingmill
HST in Intercity blue and gray livery at Slittingmill
Phil Sangwell

Since it became apparent in the seventies that electrification of all main lines would not be possible, British Railways had a diesel-powered high-speed train built. In order to keep the axle loads low, a streamlined locomotive with a fast-running and light Paxman Valenta with 2,250 hp is used at each end of the train. The trains reach a service speed of 125 mph or 201 km/h and were initially classified as class 253 and 254 multiple units. Only later were they renumbered into class 43 locomotives.

The trains run with a variable number of Mark 3 coaches and quickly spread across Britain. They are officially simply called “HST” (“High Speed Train”), but were also used as “Intercity 125” in reference to their top speed. They significantly shortened travel times compared to trains with conventional diesel locomotives. With a record of 148.5 mph (239 km/h), they are considered the fastest diesel locomotive in the world.

National Express HST with 43309 at the top in January 2009
National Express HST with 43309 at the top in January 2009
Phil Sangwell

With the privatization of British Railways, the HST came to a variety of operators. The new VP185 engine was developed before privatization, but was only installed in some of the vehicles. After the turn of the millennium, more were re-engined with new MTU engines. At the same time, some of them were replaced by new multiple units, such as the families of the 220 and 800 classes. However, due to the increased number of passengers, many remained in service. Even after 2020, many HSTs were still active in passenger transport. Today some are used by Network Rail or to ferry trains. Some were even exported to Mexico and Nigeria.

VariantValentare-engined VP185re-engined MTU
General
Built1975-1982from 1993from 2005
ManufacturerBREL, Crewe
Axle configB-B+2-2+2-2+2-2+2-2+2-2+2-2+2-2+B-B 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length loco58 ft 4 3/8 in
Wheelbase42 ft 4 in
Fixed wheelbase8 ft 6 in
Adhesive weight309,970 lbs
Axle load38,800 lbs
Power
Power sourcediesel-electric
Top speed125 mph
Starting effort36,000 lbf
EnginePaxman Valenta 12RP200LPaxman 12VP185MTU 16V 4000 R41R
Engine type2x V12 diesel2x V16 diesel
Fuel2,378 us gal (diesel)
Engine output4,500 hp (3,356 kW)
Power Plant
Boiler
Calculated Values
DMU
long distance
power cars
last changed: 01/2024
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