Class 156

Class 156
Name	Class 156
Service	1987–present
Manufacturer	British Rail Engineering Limited
Family	Sprinter
Yearconstruction	1987–1989
Numberbuilt	114
Formation	2-car sets
Capacity	130–160 seats
Operator	Abellio ScotRail, Northern Trains, TransPennine Express, Arriva Trains Wales, First North Western, First Great Western, ScotRail, Wessex Trains, Wales & Borders
Carbody	Steel
Maxspeed	75 mph (121 km/h)
Engine	Perkins P6T / Cummins
Transmission	Hydraulic

Class 156 is a British two-car diesel multiple unit introduced in the late 1980s as part of the Sprinter programme to replace first-generation British Rail diesel units such as First Generation DMUs and Class 101 stock on regional and rural services. Built by British Rail Engineering Limited at York Works and delivered during 1987–1989, the fleet saw widespread deployment across Scotland, Wales, the North West, and the West Midlands and has been operated by multiple train companies including ScotRail, Northern Trains, TransPennine Express, and several predecessors like Arriva Trains Wales and First Great Western.

Design and Development

The Class 156 was developed under British Rail's modernisation initiatives influenced by policy documents and procurement strategies of the 1980s, responding to requirements set by Network SouthEast and Regional Railways for improved reliability on secondary routes. Drawing on lessons from the Sprinter prototypes and classes such as the Class 150 and Class 155, the design emphasised simplified two-car formations for rural services similar to units ordered by ScotRail and Wales & Borders. Design priorities included durable steel car bodies influenced by the structural practices at York Works, improved passenger access inspired by British Rail's accessibility discussions, and hydraulic transmissions consistent with earlier British Rail Engineering Limited products. Contract negotiations involved British Rail's procurement teams and governmental oversight linked to transport authorities including Strathclyde Passenger Transport and Transport for Wales.

Technical Specifications

Each two-car set features a welded steel bodyshell, sliding sealed windows and end gangways derived from standards used on contemporaneous British Rail units. Power was typically provided by two Perkins 6-cylinder diesel engines per set, with some later replacements by Cummins variants during mid-life overhauls overseen by private maintenance firms and works managed at depots such as York Railway Works and Warrington facilities. The hydraulic transmission employs Voith components similar to those fitted to Class 150 units and the maximum service speed is 75 mph, suitable for secondary main lines like the Settle–Carlisle line and routes linking Glasgow with rural Highlands branches. On-board systems include air brakes meeting standards set by Rail Safety and Standards Board-influenced specifications, passenger seating layouts configurable to regional operator requirements, and multiple-unit working compatible with classes in the Sprinter family.

Service History

Delivered between 1987 and 1989, the fleet entered service on routes previously operated by veteran units such as Class 101 and Class 108, quickly becoming a mainstay for regional services across Scotland, Wales, and northern England. During the 1990s and 2000s the units passed to franchisees arising from the privatisation of British Rail, serving under operators including First North Western, Wessex Trains, Arriva Trains Wales, First Great Western, and later successor companies like Northern Trains and TransPennine Express. Their deployment included rural branch lines, commuter flows into hubs like Manchester Piccadilly, Glasgow Central, and Cardiff Central, and secondary inter-city links. Some units were cascaded between operators in franchise retendering episodes influenced by decisions from authorities such as Department for Transport.

Operations and Liveries

Throughout their careers the units wore a variety of liveries reflecting franchising and corporate identities: original British Rail regional liveries, the red and white of Regional Railways, the blue-gray schemes of FirstGroup subsidiaries, the distinctive ScotRail saltire livery, and bespoke colours applied by Arriva and TransPennine Express. Specific liveries have been applied to sets allocated to depots like Heaton and Leeds and to services promoted by regional bodies including Strathclyde Passenger Transport and Transport for Wales. Operationally, configurations have been adapted for peak commuter services into Liverpool Lime Street, rural turns on the Heart of Wales Line, and cross-border runs between England and Scotland overseen by timetable planners at companies such as Northern Rail and franchise teams reporting to Office of Rail and Road-aligned regulations.

Refurbishment and Modifications

From the 2000s onwards multiple refurbishment programmes were commissioned by operators and rolling stock leasing companies such as Angel Trains and Porterbrook to extend life and improve comfort. Works included interior re-trims, installation of modern passenger information systems compliant with standards promoted by Rail Safety and Standards Board, upgrading accessibility features to meet obligations influenced by the Disability Discrimination Act 1995 and later Equality Act 2010, replacement engines from Cummins suppliers, and retrofitting of LED lighting. Some sets received improved CCTV and driver-only operation equipment consistent with safety practices advocated by Office of Rail and Road; heavy overhauls were undertaken at depots like Doncaster Works and regional engineering centres.

Accidents and Incidents

Over decades of service several sets were involved in incidents ranging from minor collisions to severe derailments investigated by the Rail Accident Investigation Branch and its predecessor agencies. Notable investigations involved operations on routes such as the Cambrian Line and inquiries referencing operational procedures from Network Rail and franchise operators. Outcomes typically resulted in recommendations concerning operator training, speed supervision, and infrastructure maintenance overseen by agencies including Office of Rail and Road and Department for Transport to improve safety and reduce recurrence.

Category:British Diesel Multiple Units