Engineering Wonders of the World
Volume I

Forfatter: Archibald Williams

År: 1945

Serie: Engineering Wonders of the World

Forlag: Thomas Nelson and Sons

Sted: London, Edinburgh, Dublin and New York

Sider: 456

UDK: 600 eng - gl.

Volume I with 520 Illustrations, Maps and Diagrams

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{See page 85.) THE STORY OF THE SEVERN TUNNEL. The driving of a submarine tunnel is generally accompanied by great diffi- culties, but no undertaking of the kind has taxed the resource and courage of engineer and contractor more than did the Severn Tunnel, which is remarkable as being the longest submarine tunnel in the world. THE Severn estuary, while making an important addition to the total length of coast-line of Great Britain, is a very serious impediment to communication The Severn Estuary. between the western counties of England and the south of Wales. It presents a funnel- shaped opening, a hundred or more miles long, up which the tides rush as into a trap, and pile up the sea-water to a height exceeded only in the Bay of Fundy. During the ebb and flow the current is ex- tremely strong, and at low tide ever-shifting sandbanks are a source of anxiety to the navigator. In 1828 the famous engineer, Thomas Telford, threw an iron arch bridge of 150 feet span across the river at Gloucester ; and some fifty years later the Midland Railway spanned it twenty-six miles lower down by a truss bridge nearly three-quarters of a mile in