From its origins in the 1960s the future London Underground network was a significant user of steam traction; it was only with the development of electric traction that the deep level tube network became practical and eventually steam traction became limited effectively to two types of traffic: the Metropolitan lines north of Baker Street and for engineering trains on the surface sections. Apart from this traffic, which was under the control of London Transport, there remained a certain amount of steam traction used for freight traffic on the passenger lines inherited by the Underground from the LNER, such as the lines to Edgware and Ongar, until freight traffic over these lines ceased. Although the majority of steam traction on the Underground ceased in the early 1960s with the electrification of the Metropolitan line, London Transport continued to use steam traction after it ceased on the BR network for maintenance purposes and acquired a batch of ex-BR 0-6-0PTs for this traffic. This wonderful new colour album examines the last two decades of steam on the Underground. As with all Ian Allan colour albums, the book features a superb introductory text detailing steam traction's purpose on the underground up until it ceased in the early 1960s. Exclusively the only book currently in print that concentrates solely on steam traction's role on the underground, it also boasts a selection of previously unpublished colour photographs, all accompanied by informative captions.