Huge pistons open and close ducts, relieving the pressure that builds ahead of the train's noses. Some 300 miles of cold water piping run alongside the rail tracks to drain off the heat raised by air friction. The rail tunnels of the Channel Tunnel are 98 ft each, while the service tunnel is 16 ft.
A proposal for the tunnel was first put forward by Albert Mathieu-Favier, a French engineer, in 1802. Later, after 400 feet of the Channel Tunnel had been completed, political objections brought the project to a halt and the construction was not resumed until after World War-II, finally finishing in 1994.
Allwondersoftheworld.com will give you a more comprehensive idea and more amazing information about the Channel Tunnel.
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