Episode notes
In 1802 French engineer Albert Mathieu-Favier pitched Napoleon a tunnel under the English Channel lit by oil lamps, with horse-drawn coaches and an artificial island for changing horses. In 1881 Sir Edward Watkin and Alexandre Lavalley bored more than a mile on each side before British military panic stopped them, fears mocked in a cartoon of General Wolseley fleeing on a terrified lion. A 1929 plan offered floodable sumps, and Winston Churchill argued for a tunnel in the 1920s, but only air power by 1955 ended invasion worries. Britain cancelled a 1975 attempt over cost, and the 1986 Treaty of Canterbury under Thatcher and Mitterrand chose twin rail tunnels over bridges and a road tunnel, partly for fear of exhaust and driver mesmerization.
Eurotunnel was privately financed with syndicated loans and public share offers, and costs rose 80 percent from about 2.6 billion pounds to 4.65 billion. Eleven tunnel boring machines stayed inside the chalk marl, a layer of 30 to 40 percent clay that sealed out the sea, lining the bore with concrete segments as they advanced. Up to 15,000 people worked on it, and ten died. On December 1, 1990, Graham Fagg and Philippe Cozette broke through the service tunnel just 30 centimeters off line. The tunnel opened in 1994, but Eurotunnel suspended debt payments in 1995 and its concession was extended to 2086.
- The layer cake analogy: why digging too high hits porous chalk and too low hits swelling clay
- How a TBM grinds rock with tungsten carbide teeth, jacks itself forward, and places lining segments
- The Paddington Bear soft toy British workers passed through the breakthrough hole
- British boring machines driven downward, buried, and reused as electrical earthing for the line
- Economic studies finding limited gains for Britain despite a 1994 modern wonder title