The first five volumes in this series have looked at the revenue-earning wagon fleet operated by British Railways and its immediate successor, British Rail. This volume is the second of three that look at the substantial fleet of specially-designed wagons that were used for track maintenance, focussing on the many forms of early mechanized on-track plant, such as ballast cleaners, cranes and track relaying units, all of which were hauled to site. It also covers the self-propelled machines that preceded or followed the ballast trains, such as track recorders, tampers, liners and consolidators. As for the wagons themselves, only three new types were introduced, all bogie ballast hoppers, but there was a mass repainting of the existing fleet and the introduction of TOPS codes. The book includes build details, the telegraphic code names used to identify the genuine Civil Engineers wagons throughout the period and details of the number series for each type.