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British Rail's fourth design of passenger carriages was designated Mark 4, built for use in InterCity 225 sets on the East Coast Main Line between King's Cross, Leeds, Newcastle and Edinburgh. ==History and construction== A small build compared with the Mark 2 and Mark 3 designs, 314 Mark 4s were built between 1989 and 1992 by Metro Cammell/GEC-Alsthom's Washwood Heath factory to operate services on the newly electrified East Coast Main Line. Today they are operated by Virgin Trains East Coast in 30 fixed formations of nine coaches with a Class 91 locomotive and Driving Van Trailer. The Mark 4 is an all-steel coach incorporating a number of improvements over the Mark 3 stock - notably the inclusion of automatic push-button operated plug-type doors, in place of manually operated slam-doors, fully sealed gangways and Closed Emission Toilets (CET). After a period of evaluation in 1988, Swiss SIG type BT41A〔"New bogie for German ICE (Intercity Express) based on BT41", C. Freitag and S. Karch, SIG Swiss Industrial Company, Proceedings of the Institute of Mechanical Engineers, Vol 208, 1994.〕 bogies were selected rather than BREL type T4 bogies when BREL could not provide commercial guarantees on the demanding lateral ride comfort required for 140 mph running (BT41B/C refer to the bogie types used on the Mk4 DVT).〔"Mark IV Passenger Vehicles For East Coast Main Line Electrification, P H Watts and M S Hawkridge, Proceedings of the Institute of Electrical Engineers, 1989.〕 However, during the first year of operation in 1989 complaints were made about the "lively" ride of the coaches. This required modifications to the damper and spring rates of the bogies and the fitting of inter-coach "car coupler dampers" to improve damping between the vehicles.〔"The Mk 4 and Mk 5 coaches for British Rail Intercity Part 2 : testing, commissioning and service experience with the Mk 4 coach and development of the Mk 5 specification", J A Higton and D R Temple, Proceedings of the Institute of Mechanical Engineers, Vol 206, 1992.〕 Disabled access was another priority of the design, so the door vestibules were enlarged to allow a more generous turning circle for a wheelchair. With ever-increasing levels of overcrowding the so-called 'gangway passenger' had become an important consideration, so the vestibule environment was improved with carpeted walls, better lighting, sealed gangways and carriage doors, and four flip-down seats per vestibule (since removed). Many of these innovations came courtesy of the abandoned Advanced Passenger Train, upon which the Mark 4 was heavily based. This influence was most obvious with the profiled sides, intended to allow the retrofitting of tilt-equipped bogies derived from the APT. This would have allowed up to 6° of tilt; modified coaches would have been designated "Mark 4 T" but this plan was abandoned in January 1986. The business case for the Mark 4 anticipated them also being operated on the West Coast Main Line as a follow-on order after the East Coast Main Line electrification, but after the failure of the InterCity 250 project to gain Treasury support, British Rail ordered a small number of Class 90 locomotives to supplement existing locomotives on the West Coast Main Line. The Mark 4 has gained widespread praise for its exceptional crashworthiness, something that was proven in the Hatfield and Selby crashes, where experts identified the integral construction of the vehicles as being a key factor in restricting the death toll. The Class 158 and Class 159 diesel multiple units, although superficially similar, are not based on the Mark 4 bodyshell: the Mark 4 is derived from the Class 156.〔 The Iarnród Éireann Mark 4 push-pull carriages introduced on the Irish railway system in mid-2006 are of a different design, manufactured by the Spanish manufacturer CAF. The Mark 4 was the first British Rail vehicle not to use the iconic Rail Alphabet typeface for interior signage and operating notices. Via Rail Canada's Renaissance fleet of inter-city and sleeper coaches are derived from British Rail's Mark 4. They were built for the abortive Nightstar services to Europe, and adapted by Bombardier Transportation to meet Canadian requirements. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「British Rail Mark 4」の詳細全文を読む スポンサード リンク
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