British Rail Class 950

The British Rail Class 950 is a diesel multiple unit that was purpose-built by British Rail Engineering Limited's Holgate Road carriage works for the British Rail Research Division for use as a track assessment unit. It is currently operated by Network Rail.

British Rail Class 950
Class 950 at Upton in January 2014
Manufacturer	British Rail Engineering Limited
Built at	Holgate Road Works, York
Family name	Sprinter
Constructed	1987
Number built	1
Number in service	1
Formation	2 cars: DM-DM
Fleet numbers	Unit: 950001 Vehicles: 999600 and 999601[1]
Operators	Network Rail
Depots	Railway Technical Centre (Derby)[1]
Specifications
Car body construction	Steel[2]
Car length	19.930 m (65 ft 4.6 in)[2]
Width	2.816 m (9 ft 2.9 in)[2]
Height	3.774 m (12 ft 4.6 in)
Maximum speed	75 mph (121 km/h)
Prime mover(s)	2 × Cummins NT855-R5 (one per vehicle)[2]
Engine type	Inline-6 4-stroke turbo-diesel[3]
Displacement	14 L (855 cu in) per engine[3]
Power output	213 kW (286 hp) per engine
Transmission	Voith T 211 r (hydrokinetic)
UIC classification	2′B′+B′2′
Braking system(s)	Electro-pneumatic (tread)
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge

Description

Cab of vehicle 999600, showing the video camera and laser measurement equipment.

It was built in 1987 using the same bodyshell as the Class 150/1 Sprinters.^[4] It was originally classified as a Class 180,^[1] but was reclassified into the departmental series^[when?]. As part of the privatisation of British Rail, it passed to Railtrack in 1994 and then Network Rail in 2002. The unit is formed of two driving motor vehicles, numbered 999600 and 999601.

Current operations

The unit is currently painted in a plain overall yellow livery with Network Rail branding. It mostly works on branch lines, where the track quality is not good enough for larger and heavier track assessment stock. It is able to operate over most railway lines around Great Britain. The unit is based at the Railway Technical Centre in Derby.

Future

In December 2024, Network Rail announced that the unit would be withdrawn and disposed of, to be replaced by additional (modified) Class 153s.^[5]

Fleet details

Class	Operator	Qty.	Year built	Cars per unit	Unit nos.	Notes
950	Network Rail	1	1987	2	950001	Network Rail Test Train