Construction projects

Upgrading of Lötschberg Base Tunnel

BLS upgrades the Lötschberg Base Tunnel. This will put in place the prerequisites for a half-hourly Intercity service between Bern and Valais. And freight trains will therefore travel more frequently through the Base Tunnel instead of using the Lötschberg mountain line, thus increasing productivity.

7 Kilomter up to the double track extension

The Lötschberg Base Tunnel is now on the cusp of full capacity. More and more passenger and freight trains are travelling through the approximately 35 kilometre-long tunnel. The main challenge: only around 40% of the line through the base tunnel is twin track. A second 14-kilometre tunnel tube has indeed been cut, but it has not yet been equipped for railway operation. A further seven kilometres are still to be cut through, so that trains can travel continuously through the tunnel on two tracks.

In the summer of 2019, the Swiss parliament gave the green light for upgrading the Lötschberg Base Tunnel. As a result, BLS can extend the unfinished tunnel tube which already exists between Ferden and Mitholz. Planning of the partial extension of the Lötschberg Base Tunnel is already well advanced. Public disclosure is scheduled for 2020, so that, in an ideal world, construction work can start in 2022. This means the earliest it can be put into service would be from the end of 2028.

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    Partial extension means:

    • In the existing unfinished tunnel, the floor will be concreted, the vault firstly sealed with a special kind of sheeting and then clad with an inner tube of concrete. A concrete floor will also be built in.
    • Fitting the existing basic tunnel tube with railway equipment between Ferden and Mitholz:
      • a slab track will be built in. Instead of traditional ballast, the sleepers will be laid on a fixed concrete bed. In addition, catenary wires are to be installed along the entire length of the new rail tunnel.
      • Other technical equipment, such as ventilation and water systems, high-voltage plants and equipment, rail tunnel portals, radio equipment, lighting and safety equipment will be extended and adapted.
    • Installation of high-speed points in Mitholz, connecting the newly upgraded tunnel tube with the remaining single-track line. This set of points is 160 metres long, so that trains travelling at a speed of 180 kph (112 mph) can run through.
    • Installation of three additional sets of points in Ferden.This will provide the option of shifting maintenance work from one tunnel tube to another.
    • The second, existing, unfinished tunnel tube of the Engtsligen Tunnel between Frutigen and Wengy-Ey will also be fitted out with rail equipment and connected to the existing line.


    • CHF 920 million Cost
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      Projects & backgrounds
      Lötschberg Base Tunnel: a new Alpine rail link to connect Europe

      The Lötschberg Base Tunnel is the centrepiece of the BLS infrastructure. It is one of the safest, most modern and most technically complex rail tunnels in the world.

      Construction projects
      New track in the Lötschberg Summit Tunnel

      Investing in the future: The tracks in the Lötschberg Summit Tunnel were last replaced in the 1970s. BLS is now investing in a modern and sustainable track so that our customers can continue to travel safely and conveniently through the tunnel between Goppenstein and Kandersteg.