Gangway connections are provided at either end to allow passengers and staff to walk between units working in multiple. They are fitted with BSI automatic couplers and are able to work in tandem with other multiple units so fitted (Classes 142, 143, 144, 150, 155, 156, 158, 170, and 172). The arrangement of headlights on the new cab end is also different to that on the original cab end. The difference in cab sizes is visible from the outside of the vehicle, which is distinctly unsymmetrical. This new cab is smaller than the original one but still encroaches into the vestibule area, as the original positions of the exterior doors were not changed during the conversion and the original space between the vestibule and the non-cab end of the vehicle was not sufficient for a cab. After separation, the DMSL(A) vehicles were given new 'unit' numbers from 153301 to 153335, while the DMSL(B) vehicles were renumbered 57351 to 57385 (incrementing each by 50) and given matching 'unit' numbers from 153351 to 153385.īecause the vehicles were originally designed to have a driver's cab at one end only, it was necessary to retrofit one to the other end of each vehicle. The Class 155 units had been numbered from 155301 to 155335 and consisted of DMSL(A) vehicles 52301 to 52335 and DMSL(B) vehicles 57301 to 57335.
In 1990, British Rail awarded a contract for the work to Hunslet-Barclay, and it was undertaken at the firm's Kilmarnock plant in 19. The seven further Class 155 units that had been delivered to the West Yorkshire Passenger Transport Executive (WYPTE) in 1989 were not included in this plan. British Rail decided to meet this need by dividing each unit in the Regional Railways Class 155 fleet into two separate railcars that could then be converted for use independently, which would create a fleet of 70 vehicles. After the Class 155s entered service, there emerged a further requirement for the replacement of ageing railcars (mostly of Class 121 and 122) used on quieter lines.
In 19 Regional Railways took delivery of 35 two-coach Class 155 units built by Leyland Bus at its Workington factory to replace older DMUs.