Chiltern Railways testing a train with a hybrid Rolls Royce engine

Chiltern Railways, which operates services out of Marylebone station, has started testing a train fitted with a special sort of Rolls Royce engine.
The Chiltern train has been fitted with a Rolls Royce MTU hybrid drive which can run on normal diesel power at speed, but switches automatically to battery storage when travelling slowly, such as when at a railway station.
Senior managers from Porterbrook and Chiltern Railways
The hybrid engine is being supplied by Rolls Royce combines an MTU diesel