THE NEW CHANNEL TUNNEL SCENARIO. CONSTRUCTION AND OPERATION

The construction of the single-track rail tunnel would be relatively straightforward using a 4.5 M diameter pilot tunnel to investigate ground conditions. This tunnel, connected at frequent intervals to the main tunnel, would eventually become a service tunnel. Speeds would be limited to 75 mile/h in the tunnel to avoid setting up high temperatures. It is anticipated that 60 trains a day would use the tunnel in convoys of 10 in any one direction before reversing the flow. The tunnel would be closed during six hours of any day for maintenance. The extensive safety arrangements are discussed, particularly those to guard against and deal with a locomotive fire. Driving duties in the tunnel would be shared by BR and SNCF personnel, but because of differences in operating practices the drivers would have to be changed on entering the foreign country. Alternative London terminals are evaluated to give a London-Paris journey time of 4 1/2 hours.