The British Rail Class 153 Super Sprinters are single-coach railcars converted from two-coach Class 155 diesel multiple units in the early 1990s. The class was intended for service on rural branch lines, either where passenger numbers do not justify longer trains or to boost the capacity on services with high passenger volume. Description In 1987 and 1988, Regional Railways took delivery of 35 two-coach Class 155 units, built by Leyland Bus at its Workington factory, to replace older DMUs. After the Class 155s entered service, a further requirement emerged for the replacement of ageing railcars on rural lines, mostly of Class 121 and 122. 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. 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. In 1990, British Rail awarded a contract for the work to Hunslet-Barclay and it was undertaken at the firm's Kilmarnock plant in 1991 and 1992. 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. 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. The conversion involved retrofitting a driver's cab at into the spaces previously used for luggage racks at the "inside" end (B-end) of each vehicle, where each vehicle had previously been coupled back-to-back with its matching opposite in a Class 155 formation. This new cab is notably smaller than the original one at the A-end, as the positions of the exterior doors were not changed during the conversion, and it was necessary to reduce the size of the vestibule slightly in order to provide enough space for the driver. The difference in cab sizes is visible from the outside of the vehicle, which appears unsymmetrical when viewed from the sides. The arrangement of headlights on the new cab end is also different to that on the original cab end. They are fitted with BSI automatic couplers and are able to work in tandem with other multiple units