The class were externally very similar to the first batch of Class 317 EMUs, but half of the forward carriage was taken up by the engine room. Power was provided by an above-floor diesel engine driving a generator to power traction motors on the axles. A single engine was fitted at one end of the train, and the trains operated in a push-pull configuration. As part of the testing, each unit was fitted with a different diesel engine - the 3-car unit received a 1,125 bhp Paxman RP type engine, while the 4-car set had a 1,140 bhp MTU TC type. A total of seven individual vehicles were built, which were formed into two trains, 210 001 and 210 002. Set 210 001 was an outer-suburban version, with first- and second-class seating, toilets and a luggage van. Set 210 002 was an inner-suburban version provided with high-density second-class seating only. The vehicles were initially given numbers in the DMU series but quickly renumbered into the DEMU series.
Operation
Sets 210 001 and 210 002 operated in various parts of the country on trial. Crew training on the Reading-Taunton line commenced in April 1982 with a press demonstration held in May, before entering service on 5 July 1982. They operated in the London area of the Western Region: 210 001 was based at Reading TMD and operated between,, Newbury and, while 210 002 was based at Southall Depot and operated between Paddington and. In October and November 1983, 210 001 was trialled by ScotRail operating from Edinburgh and Glasgow to Dundee, Fort William and Inverness. However no more were ordered and their remit was filled by the Class 150 family of Sprinters, which, like the Class 210, were based on the Mark 3 coach bodyshell. The cars led different lives after being withdrawn. The two driving trailers were used by Network SouthEast as part of the Class 457Networker development train. Both the driving cars subsequently passed to the Electric Railway Museum, Warwickshire, one being resold in 2004 to the Eversholt Rail Group. There was a plan for a driving motor to be saved also but, after being stored at Eastleigh Works for many years, both driving motors of 002 and one of 001 were scrapped in May 2003. One of the TSOs is currently in class 455 set 455 912, as a result of the original vehicle being written off with accident damage, and the other two have been scrapped. A DTSO from set 210 002 was inserted into set 455 913, in 2013, after being rebuilt at Wolverton railway works to replace a carriage destroyed in an accident. The vehicle was converted to a 455 MSO. DMBSO 67300 is preserved by the Suburban Electric Railway Association and preserved at East Kent Railway and will become an open attraction. A Class 210 DEMU appears in the music video of the 1984 hit Smalltown Boy by Bronski Beat.
