page_title: British electric multiple units
section_title: Mark 3 coach design
hierarchical_section_title: British electric multiple units / Nationalisation / Mark 3 coach design
caption_attribution_description: English: BR Class 442, no. 2419 "BBC South Today" at en:London Waterloo on 19th July 2003. This unit is painted in en:South West Trains Express livery. Image by Phil Scott (Our Phellap)
context_page_description: An electric multiple unit is an electric train capable of operating in multiple with other EMUs that does not have a separate locomotive, typically passenger trains with accommodation in every vehicle and a driving position at each end. The term can also be used to describe a train such as the Advanced Passenger Train that was a permanent formation with a non-driving power car. As of December 2010 two thirds of the passenger carriages in Britain are formed in EMUs.
  Electric railways began in Britain in 1883 and the first EMU ran on the Liverpool Overhead Railway in 1893. In the early 20th century systems were developed where all the motors on a train could be controlled by a low voltage signal from any cab. Due to problems using steam locomotives underground, the underground railways in London and Liverpool were early adopters of 600 V DC electric traction and by 1907 underground railways in London and some provincial cities were running electric trains. A 6.7 kV 25 Hz overhead system was also used from 1908. After the railway companies were grouped in 1923, the Southern Railway greatly expanded the 3rd rail DC electrification, replacing some early AC electrification.
context_section_description: Other units were based on the all-steel Mark 3 coach design. Most are 20 m long, with two pairs of air-operated doors on each side of the coaches, built at BREL York. The first to be introduced were the AC Class 317, built in two batches from 1981–82 and 1985–87 with thyristor control systems. The DC Class 455 for inner-suburban duties in South London were built in the early and mid-1980s with recovered traction motors and equipment. The Class 318 were built by BREL for Scotland in 1985–86. The Thameslink route across London needed dual-voltage units that could change from AC to DC at Farringdon. Class 319 was built in two batches in 1987–88 and 1990 with gate turn-off thyristor control systems.Class 442 was built in 1988 for the DC South Western Main Line from London Waterloo to Southampton, Bournemouth, Poole and Weymouth. These 23 m long five-car units have air-operated plug doors at the vehicle ends and air-conditioning. Twenty-four were built in 1988-89 by BREL at its Derby works, using traction equipment from the 4Reps they replaced.
  The AC Class 321 was built in three batches in 1988–91 by BREL, with Class 322 and the 3-car Class 320.
  The 2-car DC Class 456 was built by BREL at York Works from 1990-91 to work with the Class 455s.
  In 1979 testing started on the West Coast Main Line of the Advanced Passenger Train (APT), formed of two Class 370 units composed of a driving trailer, five trailers and a power car. To increase speed the car bodies tilted, but problems meant the trains were withdrawn. The tilt technology was used twenty years later in Class 390 Pendolinos on the same route.
  In the 1980s, prototype tube train designs were trialled in order to generate feedback about future developments. These led to the 1992 tube stock that replaced the ageing 1959/62 stock on the Central line. The extension of the Jubilee line saw the introduction of the externally similar 1996 tube stock; refurbishment of the 1983 stock was being considered, but building new trains cost about the same.
  In 1980 the Tyne and Wear Metro opened over the Tyneside Electrics route, diverted through tunnels on parts of the line. New trains were introduced based on German Stadtbahnwagen B light rail units and power was taken from an overhead line at 1500 V DC. In London the automatic Docklands Light Railway opened in 1987; trains are staffed by a train captain who can drive the train in abnormal situations.
  In the 1980s and 1990s Network SouthEast developed Networker trains with micro-processor controlled three-phase AC traction motors on half the axles. The build of the first Class 465 units was split between the newly privatised British Rail Engineering Limited and GEC-Alstholm.
  Eurostar trains were ordered in 1989 to run from London to Paris and Brussels through the Channel Tunnel, then being built. They were designed to run over the DC electrified southern British network, through the AC electrified Channel Tunnel, on the French high-speed railway network (LGV Nord) at 300 km/h (186 mph) and Belgium railways. Similar to the French TGV but built the British loading gauge, the trains are 20 coaches long with two power cars, and the bogie on the passenger cars next to the power cars motored. The trains entered service in 1994.
caption: A 1980s Class 442 third-rail EMU based on the BR Mark 3 coach design
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