Tunnels (some famous examples)

Gotthard Base Tunnel

gotthard base tunnel
The Gotthard Base Tunnel (GBT) is a railway tunnel under construction in Switzerland. With a planned length of 57 km (35 miles) and a total of 153.5 km of tunnels, shafts and passages planned, it will be the longest railway tunnel in the world upon completion, ahead of the current longest, the Seikan Tunnel. The project is designed to feature two separate tunnels containing one track each. The tunnel is part of the Swiss AlpTransit project, also known as New Railway Link through the Alps NRLA which also includes the Lötschberg Base Tunnel between the cantons of Berne and Valais. Like the Lötschberg tunnel, it is intended to bypass winding mountain routes and establish a direct route suitable for high speed rail and heavy freight trains. On completion it is expected to decrease the current 3.5 hours travel time from Zürich to Milan by one hour. The two portals will be near the villages of Erstfeld, Canton Uri and Bodio, Canton Ticino. Completion has been projected for 2015 but due to delays the tunnel may only be completed as late as 2017. Nearby are two more St. Gotthard Tunnels: the 1882 railway tunnel and the 1980 road tunnel.
See http://www.answers.com/topic/gotthard-base-tunnel

Channel Tunnel

channel tunnel
The Channel Tunnel is a 50.5 km-long rail tunnel beneath the English Channel at the Straits of Dover, connecting Folkestone, Kent in England to Coquelles near Calais in northern France. A long-standing and very expensive megaproject that saw several false starts, it was finally completed in 1994.
In 2005, 8.2 million passengers travelled through the tunnel on Eurostar while in the same year Eurotunnel carried 2,047,166 cars, 1,308,786 trucks and 77,267 coaches on its shuttle trains.
In September 2006, English, Welsh and Scottish Railway (EWS) announced that due to cessation of UK-French government subsidies of £52 million per annum to cover the Channel Tunnel "Minimum User Charge" (a subsidy of around £13,000 per train, at a traffic level of 4,000 trains per annum), that freight trains post 30 November would presently stop running. EWS commented that the equivalent charge for the same distance from UK Network Rail would be £300, but that at current traffic levels the charge was effectively £8,000 per train. Accepting that the Channel Tunnel was a special case, and in light of UK Department of Industry intransigence, EWS said that they could not economically justify running trains to their customers in light of the higher charges. EWS commented that they believed that the UK Government's position was in part being defined by the current economic state and future of the Channel Tunnel operator, and its negotiations on refinancing its debt.
See also Wikipedia.