The 1955 British Rail Modernisation Plan identified a need for small, lightweight diesel locomotives and the Birmingham Railway Carriage & Wagon Company, based in Smethwick in the West Midlands, was awarded the contract to build the Class 26, Class 27 and Class 33 locomotives. All were built with Sulzer engines, and the Class 26 and 27 locomotives were split between the Scottish, Eastern and Midland regions, before being concentrated north of the border. The Class 33 locomotives were built for the Southern Region. All three classes were comfortable on freight as well as passenger turns. The locomotives were built to last, with the Class 27s the first to be completely withdrawn in 1987 and the last Class 26 taken out of service in 1993. Some Class 33 locomotives remain active on the main line. This book shows the three different classes at work and on shed, and also covers the classes into preservation.