The British Railways Pilot Scheme orders of 1955 included six Type 2 diesel-hydraulic locomotives built by the North British Locomotive Co., these being introduced during 1959 for use on the Western Region. Without operational experience, a further fifty-two locomotives were delivered between 1959 and 1962. The fleet survived intact until 1968, when approximately half of the class was withdrawn as a result of declining traffic levels across the UK, with successive National Traction Plans progressively selecting the less successful, non-standard and numerically challenged classes for removal from traffic. All fifty-eight locomotives were withdrawn by New Years Day, 1972. This book, the first of two, sets the scene surrounding the short history of the Class 22s covering the introduction of the fleet, technical aspects, appearance design, delivery and acceptance testing, works histories and allocations. Detailed individual histories of each of the fifty-eight locomotives are included.