English Electric produced the engines, 4 cylinder supercharged, RK engines designed for traction as opposed to marine use.
The two car units consisted of a Driving Motor Brake, standard open carriage which carried the engine, a driving cab and a guards compartment. The second carriage was a Driver Trailer composite, a driving cab and first and second class compartments. The combined length was 133 feet 3.5 inches weighing 88 tons seating 13 first and 114 second class passengers. In August 1959 because of the volume of traffic a centre coach was introduced into these sets.. By 1986 with the introduction of the TOPS system these units became class 205 and she became 205018.
The DMBSO unit 1118 in preservation has been coupled with the DTC unit 1129, both units were in the fatal Cowden rail crash of 15th October, 1994. Their respected front units were so badly damaged that they were cut up and the remaining units joined together. They were withdrawn from service in August 2004.