The Class 14s were designed with an axle load suitable for light line working, and were powered by a Paxman 6-cylinder Ventura engine rated at 650 hp, Voith hydraulic transmission and Hunslet triple reduction and reverse gear box.
Initially these locomotives appeared to have a busy future, however, the traffic they were built for was quickly disappearing and many were stored after only 2 years in service. Many units were purchased for work on private railways such as those operated by the National Coal Board and British Steel Corporation, where they were kept engaged until the 1980's.