British Rail Class 139

British Rail Class 139 PPM
139 002 departing Stourbridge Town
The interior of a London Midland Class 139
In service	2009-
Manufacturer	Parry People Movers
Family name	PPM
Number built	3
Formation	1 car
Capacity	20-25 seated, 30-35 standing
Operator(s)	London Midland
Line(s) served	Stourbridge Town Branch Line
Specifications
Car body construction	Stainless steel frame
Car length	8.7 m (28 ft 7 in) (139 000) 9.6 m (31 ft) (139 001-002)
Width	2.4 m (7 ft 10 in)
Height	3.2 m (10 ft 6 in)
Wheel diameter	610 mm (24 in)
Maximum speed	32 km/h (20 mph) (as in service)
Weight	12 t (11.8 long tons; 13.2 short tons) (PPM50)
Traction system	1,000–2,600 rpm flywheel
Prime mover(s)	Ford DSG423 2.3L
Power output	86 hp (64 kW)
Track gauge	1,435 mm (4 ft 8 1⁄2 in) Standard gauge

British Rail Class 139 is the TOPS classification for PPM60 model lightweightrailcars built by Parry People Movers, for use on the British rail network. The class were originally built in 2008 for operation on the Stourbridge Town Branch Line following an extensive trial with a prototype registered as a Class 999 unit.

The first newly constructed Class 139 was shown on 28 June 2008 at the Tyseley Locomotive Works Open Day. The full fleet of two units entered public service on the branch line in June 2009.

The Class 139 units are typical of the Parry People Mover concept, in that they utilise flywheel energy storage to recapture and supply the motive force for moving the vehicle. The flywheel captures the vehicle's kinetic energy when the brakes are used, and re-uses the energy for acceleration. This eliminates the need for a large diesel engine. The small onboard engine (fuelled by LPG) is used to initially bring the flywheel up to speed, to add speed to the flywheel after the vehicle is started in motion, and to provide power for the onboard systems.

The concept of using the lightweight railcar dates from 2006, when a year-long pilot scheme began on the Stourbridge Town Branch Line on Sundays, using a PPM50 unit constructed in 2002 and numbered as 999 900 under TOPS. The success of this trial led to the provision of regular services using the technology in the franchise plans for the new West Midlands Franchise. Following the award of the franchise to London Midland, they placed an order for two PPM60 units with Parry People Movers, through Porterbrook leasing, with the service itself operated for them by Pre Metro Operations.

These two units are 139 001 and 139 002, composed of vehicle numbers 39001 and 39002 in the British carriage and wagon numbering and classification system. The vehicles are mechanically similar to 999 900, but are approximately one metre longer. They were intended to start operating on the Stourbridge Town branch in 2008. In January 2009 it was confirmed that 139001 was still undergoing testing at Chasewater Railway and 139002 was still not completed.