In the mid-1950s there were rumours that the Northern line was to be upgraded from manual operation to an automated line. This involved twelve manned signal boxes with a total of forty-one signalmen, eventually reduced to thirteen signalmen after automation. Automating the Northern Line describes how the line was operated manually, then progressed via the various stages involved in the modernisation to a fully automated line, from the point of view of a signalman/regulating room operator who was working on the line throughout the whole period. This book explains, with the help of photographs, the technology involved, including the test machinery initially used, and also the difficulties encountered by the staff who had to operate this new control system.