Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The 101 Class of NIR consisted of three mainline diesel-electric locomotives designed for use with the Enterprise passenger services between Belfast and Dublin. The intention was to reduce the time for the 180 km (112 3/4-mile) journey to two hours. The design of the superstructure and bogies was carried out by the Hunslet Engine Company of Leeds with English Electric / AEI being responsible for the electrical traction. The contract stipulated a ten month delivery period but with Hunslet''s workshops already committed, the superstructure and assembly was contracted out to (BREL), Doncaster, Hunslet providing the bogies. They were of Bo-Bo wheel arrangement and fitted with CSVT Mk. II 1,350 horsepower (1,010 kW) engines.