Tunnel

A tunnel is a passage through a mountain or under a waterway, road or railroad.

It may be for pedestrians and/or cyclists, for general road traffic, for motor vehicles only, for rail traffic, or for a canal.

Various combinations are also possible.

The central part of a metro network is usually built in tunnels. To allow non-level crossings, some lines are in deeper tunnels than others. At metro stations there are often also pedestrian tunnels to walk from one platform to another.

At train stations of ground-level railways there are often one or more pedestrian tunnels under the railway to reach the platform(s).

Construction

Shallow tunnels are of the cut-and-cover type (if under water of the immersed-tube type), deep tunnels are excavated. For intermediate levels, both methods are possible.

Cut-and-cover is a method of tunnel construction where a trench is excavated and roofed over. Strong supporting beams are necessary to avoid the danger of the tunnel collapsing.

Wartime tunnels

Castles, sappers

trench warfare: Crimea, US Civil War, WWI

Germany WWII, V2 factories, slave labor

North Korea, infiltrators, midget subs...

Japan, Corregidor, etc. (Neal Stephenson's Cryptonomicon?)

Vietnam, tunnel rats ("Platoon"?)

Examples of tunnels

• The Lincoln Tunnel between New Jersey and New York is the busiest vehicular tunnel in the world.
• The Sapperton Tunnel[?] in the Thames & Severn Canal in England, dug through hills, which opened in 1789, was 3.5 km long and allowed ship transport of coal.
• The Box Tunnel in England, which opened in 1841, is one of the oldest railway tunnels in the world. It is dug and has a length of 2900 m.
• The Atlantic Avenue Tunnel, Brooklyn, New York is the world's oldest underground railway tunnel in a street, built in 1844 by the cut-and-cover method for the Long Island Railroad. It is 800 m long.
• The Channel tunnel between England and France.

See also: List of tunnels, Wind tunnel.

Common misspelling and questions (FAQ)

unnel  tnnel  tunel  tunel  tunnl  tunne  utnnel  tnunel  tunnel  tunenl  tunnle  tunne  ttunnel  tuunnel  tunnnel  tunnnel  tunneel  tunnell  5unnel  runnel  funnel  6unnel  gunnel  6unnel  yunnel  gunnel  t7nnel  tynnel  thnnel  t8nnel  tjnnel  t8nnel  tinnel  tjnnel  tuhnel  tubnel  tujnel  tujnel  tumnel  tunhel  tunbel  tunjel  tunjel  tunmel  tunn3l  tunnwl  tunnsl  tunn4l  tunndl  tunn4l  tunnrl  tunndl  tunneo  tunnek  tunne,  tunnep  tunne.  tunnep  tunne;  tunne.  yunnel  tyunnel  tunnels 


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