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Class 43 (British Railways/Ruston Paxman 2,250hp Diesel-Electric) High Speed Train

The High Speed Train (HST), powered by a Class 43 powercar at either end of the train, is arguably the most successful diesel powered high speed train in the world. The HST bought 125mp/h speeds to British Rail Inter City expresses in the late 1970s, helping to revitalise long-distance rail travel when it was at a low ebb. Indeed, it is not an exaggeration to say the HST changed the face of rail travel in the UK once and for all and helped stem a seemingly unstoppable decline. The futuristic streamlined shape of the power cars (which can surely be considered a British design classic) quickly became the face of BR publicity [1]. The HST was an instant hit with the public with passenger numbers on the HST services rising by fifteen percent within the first two months of operation. The HST still holds the official speed record for a diesel hauled passenger train of 148 mp/h.

43 185 in Intercity livery (operated by GWR) at London Paddington


Information
Number built: 197
Built: 1976-82
Builder: BREL Crewe
Refurbished by Brush Traction (2006-9)
Engine: (Original) Paxman Valenta 12RP200L diesel
(Refurbished) Paxman 12VP185 or MTU 16V4000 R41R diesels
Power: (Valenta) 2, 250 hp (1, 678 kW)
(12VP185) 2, 100 hp (1, 565 kW)
(MTU) 2, 250 hp (1, 676 kW)
Wheel arrangement: Bo-Bo

The Intercity 125 High Speed Train was introduced in October 1976 [2] following trials earlier in the decade with the prototype HST Class 41/252. Originally, the HST was designated a diesel electric multiple unit with units allocated to Western Region numbered Class 253 and those on Eastern Region Class 254.

However, in the 1980s the power cars were allocated the TOPS number Class 43 (the original Class 43 was the "Warship" diesel-hydraulic locomotive), they are after all proper locomotives capable of independent operation (though this is fairly rare in practice), the Mark 3 coaches they haul/propel differ from loco-hauled Mark 3s with different electric systems and a lack of buffers and can only work properly with Class 43s. The Class 43 only has a driving cab at the streamlined end, the prototype Class 41 also had auxiliary cab controls for shunting at the other end but this was not continued with the production power cars.

Ironically, the HST only came about because of a lack of funds for electrification of more main line routes after the completion of the West Coast Main Line [3]. The HST was devised as a stop-gap... that has so far lasted over forty years! Although they have been slowly replaced from some of their original routes they have been cascaded onto other routes and should continue to serve well into the 2020s. In the mid to late 2000s the fleet was heavily refurbished with the original Paxman engines replaced mostly by MTU units [4] though some have also been fitted with Paxman VP185 diesels since the early 1990s. 

The Class 43 has also been exported to Australia where power cars heavily based on the Class 43s powered the XPT which is still in service [5]. In the late 1980s a small number of Class 43s were taken out of service, fitted with buffers, and formed driving van trailers for the new Class 91 which replaced the HST on the newly electrified East Coast Main Line. Once purpose built DVTs had been built the modified Class 43s were returned to service [6]. Withdrawn power cars have been exported to Mexico and Nigeria.

The Class 43 currently serves with ScotRail and has served with a number other companies in the privatised era including GWR and Cross Country. The ScotRail sets are shorter than older sets to enable improved acceleration. There are also a number of full-length HST sets in use for rail holidays and tours. Some cars are also in service with Network Rail in the New Measurement Train and other departmental uses.

Colas operated 43 272 hauls a test train through Chepstow

Cross Country 42 239 at Birmingham New Street

43 018 preserved in original BR livery at Crewe Heritage Centre

GWR 43 029 at Newport

The New Measurement Train at Sheffield



[1] Chris Heaps, BR Diary 1968-1977 (Ian Allan, 1988) p. 99
[2] Brian Haresnape, High Speed Trains (Ian Allan, 1983) p. 51
[3] Colin J. Marsden (ed.), "The Production HSTs", Modern Locomotives Illustrated No. 208 August-September 2014 (The HST Part 1: The BR Days) p. 28 
[4] Colin J. Marsden, Traction Recognition (Second Edition) (Ian Allan, 2009) p. 34
[5] Marsden, MLI 208 p. 71
[6] Marsden, Traction p. 36