British Rail Class 158

British Rail Class 158 Express Sprinter
A ScotRail Class 158 at Scotscalder
ScotRail interior in 2024
In service	17 September 1990 – present
Manufacturer	British Rail Engineering Limited[1]
Built at	Derby Litchurch Lane Works[1]
Family name	Sprinter
Replaced	Locomotive-hauled trains BR First-Generation DMUs
Constructed	1989–1992[1]
Number built	180 (8 converted to Cl. 159/1)
Number in service	171[2]
Number scrapped	1
Formation	2 or 3 cars per unit
Fleet numbers	(See § Fleet details)
Capacity	NT: 138 or 142 seats per 2-car unit, 207 seats per 3-car unit[3] SWR: 125 seats per 2-car unit[4] TfW: 138 seats per 2-car unit[5]
Operators	East Midlands Railway Great Western Railway[6] Northern Trains ScotRail South Western Railway Transport for Wales Rail
Specifications
Car body construction	Welded aluminium[1]
Car length	22.57 m (74 ft 1 in)[1]
Width	2.70 m (8 ft 10 in)[1]
Height	3.73 m (12 ft 3 in)[7]
Doors	Double-leaf plug (2 per side per car)[1]
Maximum speed	90 mph (145 km/h)[1]
Weight	38.5 tonnes (42.4 short tons; 37.9 long tons) per car[1]
Axle load	Route Availability 1[1]
Prime mover(s)	Units 158701–158814: Cummins NTA855-R1 Units 158815–158862: Perkins 2006 TW-H Units 158863–158872: Cummins NTA855-R3 Units 158901–158910: Cummins NTA855-R1 (one per car, unit numbers as built)
Engine type	Inline-6 4-stroke turbo-diesel[8][9]
Displacement	Cummins: 14.0 L (855.00 cu in)[8] Perkins: 12.2 L (742.64 cu in)[9] (per engine)
Power output	NTA855-R1: 260 kW (350 hp)[1] 2006-TWH: 260 kW (350 hp)[1] NTA855-R3: 300 kW (400 hp)[1]
Transmission	Voith T 211 rz or T 211 rzz (hydrokinetic)[1]
Acceleration	0.8 m/s2 (2.6 ft/s2)[10]
UIC classification	2-car: 2′B′+B′2′ 3-car: 2′B′+B′2′+B′2′
Bogies	Powered: BREL P4-4 Unpowered: BREL T4-4
Braking system(s)	Pneumatic (disc)[1]
Safety system(s)	AWS TPWS ETCS (158818-158841 only)[11]
Coupling system	BSI[12]
Multiple working	Within class, and with Classes 14x, 15x, and 170[12]
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge

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.^[13][14]

The Class 158 was constructed between 1989 and 1992 by British Rail Engineering Limited (BREL) at its Derby Litchurch Lane Works. The majority were built as two-car sets, some three-car sets were also produced. During September 1990, the first Express Sprinters were operated by ScotRail; the type was promptly introduced to secondary routes across the Midlands, Northern England, Wales and the South West. The Class 158 enabled the replacement of large numbers of elderly DMUs but also several locomotive-hauled trains as well; this was partially accomplished via the cascading of existing Sprinter units onto other routes.^[15] To capitalise on the Class 158's improved onboard amenities in comparison to other rolling stock in use for regional services, the Alphaline branding was launched during the mid-1990s; it was also used for a time in the post-privatisation era.

As a result of British Rail's privatisation in the mid 1990s, the Class 158s were divided amongst various newly-created operators broadly along their existing routes. Due to their relatively young age at that time, most operators elected to retain them for the following decades. Several, such as Northern Rail and Arriva Trains Wales, had their Class 158 fleets modernised and refitted with various new facilities, such modifications often including greater accessibility, onboard passenger information systems, Wi-Fi connectivity, and toilet retention tanks. By the 2020s, many Class 158 operators have started to or have replaced the type with newer rolling stock, such as the Class 170 Turbostar, Class 185 Desiro, and Class 197 Civity multiple units.