It was developed by the Ulster Transport Authority (UTA) as a progression of the earlier Multi-engined Diesel (MED).

The MED concept, while suitable for short commuter links, was not considered so for the Northern Counties Committee section, with its main line from Belfast to Derry where speeds of up to 110 km/h (68 mph) were required.

The first ten power cars being intended for the Derry line trains, with the others being for the Belfast local services.

The power cars were originally fitted with a 275 hp (205 kW) Leyland engine, mounted beneath the chassis and driving both axles on the rear bogie through a torque converter.

58 suffered a collision with a motor vehicle on a level crossing in July 1958, being written off and scrapped after just six weeks in service.