A diesel multiple unit or DMU is a multiple-unit train powered by on-board diesel engines. A DMU requires no separate locomotive, as the engines are incorporated into one or more of the carriages. Diesel-powered single-unit railcars are also generally classed as DMUs. Diesel-powered units may be further classified by their transmission type: diesel–mechanical DMMU, diesel–hydraulic DHMU, or diesel–electric DEMU.
Pacer was the operational name of the British Rail Classes 140, 141, 142, 143 and 144 diesel multiple unit railbuses built between 1980 and 1987. They were inexpensively developed using a passenger body based on the Leyland National bus on top of a chassis based on the HSFV1 research vehicle. The railbuses were intended as a short-term solution to a shortage of rolling stock, with a lifespan of no more than twenty years. As modernised replacements were lacking, the Pacer fleet remained in service on some lines until 2021, 37 years after their 1984 introduction.
The British Rail Class 08 is a class of diesel–electric shunting locomotives built by British Railways (BR). As the standard BR general-purpose diesel shunter, the class became a familiar sight at major stations and freight yards. Since their introduction in 1952, however, the nature of rail traffic in Britain has changed considerably. Freight trains are now mostly fixed rakes of wagons, and passenger trains are mostly multiple units or have driving van trailers, neither requiring the attention of a shunting locomotive. Consequently, a large proportion of the class has been withdrawn from mainline use and stored, scrapped, exported or sold to industrial or heritage railways.
The British Rail Class 156 Super Sprinter is a diesel-hydraulic multiple unit passenger train. A total of 114 sets were built between 1987 and 1989 for British Rail by Metro-Cammell's Washwood Heath works. They were built to replace elderly first-generation DMUs and locomotive-hauled passenger trains.
The British Rail Class 108 diesel multiple units were built by BR Derby from 1958 to 1961, with a final production quantity of 333 vehicles.
The British Rail Class 158 Express Sprinter is a diesel multiple unit (DMU) passenger train. It is a member of the Sprinter series of regional trains, produced as a replacement for British Rail's first generation of DMUs; of the other members, the Class 159 is almost identical to the Class 158, having been converted from Class 158 to Class 159 in two batches to operate express services from London Waterloo to the West of England.
The British Rail Class 153 Super Sprinter are single-coach diesel-hydraulic railcars which were 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.
The British Rail Class 159 is a class of British diesel multiple unit passenger trains of the Sprinter family, built in 1989–1992 by British Rail Engineering Limited (BREL)'s Derby Litchurch Lane Works as Class 158. Before entering traffic, the original 22 units were modified at Rosyth Dockyard to Class 159 to operate services from London Waterloo to Salisbury and Exeter St Davids, replacing various locomotive-hauled passenger trains.
The British Rail Class 121 is a single-car double-ended diesel multiple unit. 16 driving motor vehicles were built from 1960, numbered 55020–55035. These were supplemented by ten single-ended trailer vehicles, numbered 56280–56289. They have a top speed of 70 mph (113 km/h), with slam-doors, and vacuum brakes. The driving motor vehicles were nicknamed "Bubble Cars" by some enthusiasts.
The British Rail Class 116 diesel multiple units were built by BR Derby from 1957 to 1961. Introduced as part of the British Railways Modernisation Plan in the mid 1950s, as with other first generation DMUs the 116 was intended to replace steam trains and reduce costs across the rail network. Alongside Metro-Cammell, BR Derby had prior experience with DMUs, having developed a Lightweight Unit, and so was awarded a contract for a new design.
The British Rail Class 150 Sprinter is a class of diesel-hydraulic multiple unit passenger trains, developed and built by British Rail Engineering Limited at York Carriage Works between 1984 and 1987 for use on regional services across Great Britain. The type is a second-generation design, built to more modern standards and based on BR's Mark 3 body design for longer-distance services. It was developed alongside the lower-cost Pacers, which were built using bus parts, for use on short-distance services. Two prototype units were built, followed by 135 production units in two batches. Subsequently, further members of the Sprinter family were developed and introduced to service, including the Class 155, Class 156, Class 158 and Class 159.
Class 142 diesel multiple unit passenger trains were built for British Rail (BR) from 1985 to 1987, with a high level of commonality with the widely-used Leyland National bus. They are part of the Pacer family of railbuses. The last set was withdrawn from service in 2020.
The British Rail Class 143 are diesel multiple unit passenger trains, part of the Pacer family of passenger trains introduced between 1985 and 1986.
The British Rail Class 155 is a diesel multiple unit passenger train. These DMUs were built by Leyland Bus at Workington between 1987 and 1988 as part of BR's replacement of its ageing first-generation diesel fleet. 42 units were originally built, of which only 7 remain; the other 35 units were converted to Class 153 railcars.
The British Rail Class 210 was a type of diesel-electric multiple unit (DEMU) passenger train designed and constructed by British Rail Engineering Limited's Derby Litchurch Lane Works.
The British Rail Class 125 was a design of three car Diesel Multiple Unit built by BR Derby at Derby Works in 1958. They were almost identical in appearance to the Class 116.
The Sprinter is a family of diesel multiple unit trains in use on the British railway system. They were built in the 1980s and early-1990s by British Rail Engineering Limited (BREL), Metro-Cammell and Leyland. Sprinters operate in almost every part of Great Britain, from rural branch lines to commuter expresses into major cities.
Diesel multiple units and railcars are trains, usually with passenger accommodation, that do not require a locomotive. Railcars can be single cars, while in multiple units cars are marshalled together with a driving position either end. As of December 2010, 23 percent of the rail passenger cars used on Network Rail are part of a diesel multiple unit.
The British Rail Class 769 Flex is a class of bi-mode multiple unit (BMU) converted by Brush Traction, and running in service with Northern Trains. The train is a conversion of the existing Class 319 electric multiple unit (EMU), a conventional unit type which had become surplus to requirements during the 2010s.
