This is one of the numerous ‘Simplex’ locos, built by the Motor Rail and Tramcar Co. of Bedford in 1933 as No. 5646. It is fitted with a 4-litre twin-cylinder Dorman diesel engine, with transmission by a Dixon-Abbot gearbox and roller chains. It is planned to fit an electric ignition system to the Simplex in due course.
There is also another earlier bow-framed Simplex loco at the railway, although it is currently engine-less and requires major restoration.