British Rail Class 129

British Rail Class 129
In service	1955–1973
Manufacturer	Cravens
Number built	3
Number scrapped	All
Operator(s)	British Rail
Specifications
Car length	57 ft 6 in (17.53 m)
Width	9 ft 3 in (2.82 m)
Height	12 ft 9 in (3.89 m)
Maximum speed	70 mph (113 km/h)
Weight	30 long tons (30 t; 34 short tons)
Prime mover(s)	Two BUT, 150 hp
Power output
Track gauge	4 ft 8 1⁄2 in (1,435 mm)

The Class 129 was a class of single-car Diesel Multiple Unit built in 1955 for British Rail. Only three were built by Cravens and were introduced in 1958. The class was built for parcels traffic like the Class 128. One unit (55997) survived into departmental service being named 'Hydra'. The driving ends of a Class 129 car bore a visible similarity to that of the British Rail Class 105, also built by Cravens.

Table of orders and numbers

Lot No.	Type	Diagram	Qty	Fleet numbers	Notes
30418	Non-ganwayed Motor Parcel Van	531	3	M55997–55999

Departmental Usage

One unit, M55997, was converted as a test bed for hydrostatic drive in 1980, was renumbered RDB 975385, and named Laboratory 9 ‘Hydra’.

It was fitted hydrostatic transmission having the normal Leyland 680 six cylinder engine driving two Rexroth Hydramatic axial piston pumps. Each pump supplied fluid to a Volvo fixed displacement compact axle-end motor which drove the axle directly. The maximum system pressure was in the order of 400 bar (40 MPa; 5,800 psi).

This arrangement was only fitted to one bogie, the other one retaining its normal drive but with the cardan shaft disconnected.

The unit was finally scrapped by Vic Berry at Leicester.