Of the 51,000 miles of railway lines in Britain, over 1,800 miles are renewed every year. No longer is each rail manhandled by the men of the permanent way. Mobile cranes remove the old track, complete with sleepers, and replace it with prefabricated lengths. This has made the work less arduous, and the period during which the line is closed to traffic is considerably shortened. This account of the work as seen from the point of view of the crane inspector