The British Rail Class 155 is a diesel multiple unit. These DMUs were built by Leyland Bus at Workington between 1987 and 1988 as part of British Rail's replacement of its ageing first-generation diesel fleet. 42 units were originally built, however only 7 remain; the other 35 units were converted to railcars.
History and description
The Class 155 train is made up of two 23 metre coaches fitted with Cummins NT855R5 285hp engines and Voith transmission. The fleet was part of the "Super Sprinter" build and was built by Leyland with a similar construction technique to the Pacers, with extensive use of Avdel rivets holding pre-formed panels together in a lightweight body on a welded floor assembly. The large number of windows makes the vehicles look unusually long, although the fact that the vehicles are very long for such a lightly built body has led to a slight sag being apparent in certain coaches. Introduction was rapid, but teething troubles soon emerged. The units were the first BR DMUs with sliding-plug automatic doors which closed to provide a smooth bodyside rather than sliding back into the bodyshell. These doors did not work properly and there were reports of them opening while the trains were in use. Consequently, the fleet was taken out of use and modified, with the 156s taking over their diagrams. Following rework the fleet performance improved substantially. An emerging requirement for replacement rural lines stock saw BR decide to convert the Regional Railways fleet into single-cars to replace the elderly121 and 122 "Bubblecar" units. These single-car sets, introduced 30 years previously, had been threatened with withdrawal and replacement by the Pacer fleet, although the Pacers had proved to be unable to work the sharply-curving steeply-graded branchlines involved. Instead the Pacers were moved to replace a number of Class 150s, the 150s took over certain 156 diagrams, and the 156s took on the 155 services which were not handed over to the new Class 158s. The 155s emerged from the workshops as single carClass 153s, and were put to work augmenting two car units and on the quiet Cornish, Welsh, North-Western, Norfolk and Lincolnshire branch lines. They do not operate North of the Scottish border. However, West Yorkshire Passenger Transport Executive refused to allow the seven units which they owned to be converted, and these were merely modified to operate reliably in original form. The conversion to single car units was notable for not requiring any external doors to be moved, although this has led to the No.2 cab being unusually cramped, despite being extended into the vestibule area.
