Unlike the MEDs and MPDs with their low - powered underfloor engines and mechanical transmissions spread through the train, the new units had a single English Electric engine of , fitted in a compartment between the driving cab and the passenger saloon, and electric transmission. Whilst construction was carried out at the UTA's York Road works in Belfast they imported underframes and body parts. This order comprised parts for the construction of eight power cars and the modification of existing coaches, The 70 Class were first introduced on the former Northern Counties Committee section but were later also worked cross-border trains.