LYCOS RETRIEVER 
Channel Tunnel: English Channel
built 629 days ago
The opening of the Channel Tunnel in 1994 turned the centuries old dream of a fixed link between the UK and mainland Europe into a reality. The Channel Tunnel is 50km long, with the 39km undersea section being the longest undersea tunnel in the world. On average, the tunnels lie 40 metres below the seabed of the English Channel.
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The tunnel is now fully functioning. It extends for 31 miles under the English channel (or the French La Manche depending on your perspective). The deepest point is 114.9m below sea level, compared to the average London Underground depth of 24.38m. There are two main train tunnels, plus a small maintenance access tunnel.
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Other trains were in the tunnel at the time of the incident. There were three trains ahead of train 7539, all of which drove out of the English portal as normal. Two trains entered the tunnel behind the incident train: a lone locomotive directly behind train 7539 (from which the driver evacuated to the service tunnel) and a passenger train behind that (which reversed out through the French portal).
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On the English side an average of 150m/week tunnel progress was achieved while in France the weekly average was about 110m/week. This difference was due to the different TBM design due to more adverse tunnelling conditions.
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After 800 feet of tunnel had been excavated, a second shaft (No 2) was sunk at Shakespeare Cliff in February 1881. The boring machine used was designed by Thomas English of Dartford and was capable of cutting a depth of 5/16" for every revolution of the cutting head at a rate of two revolutions per minute, although it was hoped this could be improved later.
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English Channel