Longest single-track railway tunnel

What to remember

Under the Bernese Alps, some 400 m below the older Lötschberg Tunnel, the base tunnel links Frutigen in the canton of Bern with Raron in Valais. Its length, 34.577 km, makes it the longest single-track railway tunnel in the world.

It has two tubes, but they run side by side as single tracks for only 12 km; along 22 km, trains share a single track. That section greatly limits capacity, and the tunnel was saturated within a few years of opening. Work to fully equip the second tube was decided in 2023, to begin in 2026.

One of the two centrepieces of the New Railway Link through the Alps (NRLA), it was begun in 1999, broken through in 2005, completed in June 2007 and opened to trains in December 2007. It was the longest land railway tunnel until the Gotthard Base Tunnel opened. The initial project was estimated at SFr4.3 billion ($3.59 billion). The tunnel saves up to an hour on the crossing of the Alps.