====== Tunnels and underground networks ======


Tunnels are useful to pass hills or mountains and also to build underground networks or undersea tunnels.


===== I.Simple tunnel =====


Select the tunnel tool and click on one of the extremity of the future tunnel, is the both facing extremities allow the construction of a tunnel entry, the tunnel is built :{{  :fr:tunnel01.jpg  }}


===== II.Complex constructions =====


==== 1.Choose the adapted view ====


As seen in the tutorial [[http://www.simutrans-france.fr.nf/doku.php?id=en:interface|Settings and interface]] there are two ways to see under the ground. To have a global looking at the underground networks, it's better to use the normal underground view <wrap tip>keyboard shortcut "shift+u"</wrap>, to build easily an underground network in one or more layers you'd better use the layer sliced view :{{  :fr:tunnel02.jpg  }}


<WRAP important>Build under the ground with the global undergroun view is possible but not very practical.</WRAP>


==== 2.Build a complex underground network ====


It's possible to build just a tunnel entry instead of a complete tunnel by holding down ctrl key while building :{{  :fr:tunnel03.jpg  }}Then the underground constructions are the same as ground's ones but instead of using a way tool you have to use the tunnel tool which works the same way :{{  :fr:tunnel04.jpg  }}


Then you can build stations, signals and electrifications as you want.


==== 3.Underground slopes ====


To make an underground slope, use first the adapted artificial slope tool on a way extremity to make a down or up slope.{{  :fr:tunnel05.jpg  }}Then vary the height of the layer sliced view to go to the lower or higher layer and extend the network.{{  :fr:tunnel06.jpg  }}


==== 4.Undersea tunnels ====


You can build undersea tunnels by the same way but of course you have to take care of the sea deepness : more the sea is deep and more the tunnel must be deep.{{  :fr:tunnel07.jpg  }}


<WRAP box>Next tutorial : [[http://www.simutrans-france.fr.nf/doku.php?id=fr:elevatedway|Elevated ways]] </WRAP>