Railway tunnels are nearly as old as railways. The first one was built in 1826 on the line between Liverpool and Manchester. Later on, the development of railways in the late 1880's led to a dramatic development of railway tunnels.
In the recent years the development all over the world of high speed railway lines has spurred the construction of a large amount of new tunnels, rather long and deep especially in mountainous regions where base tunnels need to be built in order to obtain railway lines with minimum gradients connected with the valley level.
The most known tunnels are the two Swiss base tunnels which cross the Alps from North to South: the Lötschberg tunnel (34 km) already under operation and the Gotthard Base Tunnel (57 km), which one will be finished will become the longest tunnel in the world.
Two other long tunnels are planned in the Alps, one between Austria and Italy, the Brenner, and one between france and Italy, the Mont Ambin tunnel on the Lyon-Turin railway line.
Other projects in the phase of discussion which might eventually be built in store are a new railway base tunnel between Spain and France through the Pyrinees and eventually a future tunnel linking Europe and Africa through the strait of Gibraltar.