Prior to the decision in the 1955 Modernisation Plan to develop the DMU as a replacement for steam haulage on branch lines and secondary routes, British Rail had introduced a number of DMU vehicles, (the lightweight units in particular) to gauge the impact of this type of rolling stock on revenue and expenditure over routes that were potentially threatened with closure. These units were introduced to service in several parts of the country including the West Riding and the northwest with considerable success. Although the units were largely constructed at Derby Works, a small number of private contractors, such as Metropolitan-Cammell, were also involved. Apart from the DMUs, the programme also included two single-car units as well as a two-car set that was converted to battery operation for use on the Aberdeen-Ballater line. As non-standard types, the units were largely withdrawn by the late 1960s but a number saw subsequent service in Departmental use. A handful of the types, including one of the single units and the two-car battery set, survive in preservation. This book will examine the units in detail, accompanied by scale drawings and informative text on the construction, operation and history of the units. It will also contain an appendix detailing the history of each individual vehicle (date of introduction, allocation, withdrawal, fate, etc). Highly illustrated with both mono and colour illustrations and 4mm scale drawings, this will be sought after by enthusiasts nationwide.