Costing at the time £1.8 million to complete, the Severn Tunnel was a Victorian engineering triumph, and for over a century it remained the longest rail tunnel in Britain. Construction had begun in 1873 but came to a standstill after the workings were inundated by water in 1879. An accomplished civil engineering contractor, Thomas Andrew Walker (1828–89) had worked on railways in Canada, Russia and Africa as well as on London's new underground lines; he was therefore well qualified to complete the Severn Tunnel, which was achieved in 1886. First published in 1888, Walker's first-hand account of the problematic project remains an engaging source for railway and engineering historians, and its detailed account of the ground encountered will also interest geologists. Replete with plans and maps, reissued here is the second edition of 1890, the year following Walker's death, which is likely to have been hastened by overwork.