British Rail Class 210
The BR Class 210 was a pair of prototype diesel-electric multiple unit sets built at BREL Derby in 1981, designed to evaluate a new concept for BR's next generation of inter-city DMU: a diesel-electric power arrangement using underfloor-mounted engines driving electric traction motors, rather than the hydraulic transmission used in the Sprinter family. The two prototype sets — 210 001 and 210 002 — were built to explore whether a diesel-electric EMU-derivative could offer a more sophisticated and comfortable product for longer-distance services than the conventional hydraulic DMU designs then being developed.
The Class 210 was unusual in conception. Rather than developing an entirely new vehicle from scratch, BR adapted the body structure of the Class 317 electric multiple unit, then being developed for the Bedford–St Pancras electrification, to create a diesel-electric version. Each set used a Paxman Valenta prime mover — the same engine that powered the High Speed Train power cars — to generate electricity for the traction motors. The intention was to offer HST-quality performance in a multiple-unit format suitable for routes that could not justify full electrification.
In practice, the two prototypes proved mechanically complex and difficult to maintain. The combination of a diesel generating set, electric traction equipment, and a body structure derived from electric multiple unit practice created a vehicle that was considerably heavier and more expensive to operate than the hydraulic DMUs being developed in parallel. The BREL Sprinter concept, with its simpler hydraulic transmission and purpose-designed lightweight body, proved to be a more practical and economical solution for BR's regional requirements. The Class 210 project was cancelled, and both prototype sets were withdrawn in 1987 having never entered revenue service on a regular basis. Neither was preserved.
The Class 210's importance lies not in its own service career, which was negligible, but in the information it provided to BR about the relative merits of diesel-electric versus hydraulic transmission for multiple-unit traction — information that informed the decision to proceed with the hydraulic Sprinter family as the standard for BR's second-generation DMU fleet.
Design and development
The Class 210 concept arose from a BR interest in exploring diesel-electric multiple unit technology as an alternative to the hydraulic Sprinter approach. BREL Derby adapted the underframe and body concept of the Class 317 EMU to create a diesel-electric power unit, using the Paxman Valenta prime mover to drive an alternator supplying electric traction motors. The heavyweight construction inherited from the EMU body, combined with the complexity of the diesel-electric arrangement, made the concept economically unfavourable compared to the purpose-built lightweight hydraulic Sprinter being developed simultaneously.
Service and withdrawals
The two prototypes were evaluated on Western Region Thames Valley services from 1981. Neither entered regular revenue service as a production type; the project was cancelled and both sets withdrawn in 1987 after it became clear that the hydraulic Sprinter concept (Classes 150, 155, 156) offered a lighter, simpler, and cheaper solution. The Class 210 influenced later thinking about DEMU design without producing a production class.
Identification features
Three- or four-car diesel-electric multiple unit.
Numbers and names
210Two prototype sets onlyTwo prototype sets: 210 001 (three-car) and 210 002 (four-car). Neither carried TOPS numbers.
Notable locomotives
- 210 001, 210 002 (1981, scrapped)
Allocations and regions
Western Region, based at Reading for evaluation trials. Used on Thames Valley services during the evaluation period.
