Revised Project Opens for Public Consultation
Swiss railway operator and infrastructure manager BLS has presented plans for the full expansion of the Lötschberg Base Tunnel. Once the project is completed, the entire 35-kilometre route between Frutigen and Raron will operate as a continuous double-track railway.
According to the official BLS announcement, the revised construction plans are open for public consultation from August 17 to September 15, 2026. The permit for the previously planned partial expansion is already legally valid, so the new consultation covers only the changes required for the full double-track configuration.
Most approved surface facilities, construction sites, environmental measures and protective infrastructure will remain unchanged.
Another Seven Kilometres Must Be Excavated
Only the 14-kilometre section between Raron and Ferden currently has two fully equipped railway tracks.
A second 14-kilometre tunnel bore has already been excavated between Ferden and Mitholz, but it remains an unfinished shell. Tracks, electrical equipment, signalling, communications and safety systems must still be installed before trains can use it.
On the remaining seven-kilometre section between Mitholz and Frutigen, the second bore has yet to be excavated. The revised project also includes an additional emergency stop near Mitholz and changes to the sequencing and organization of the construction programme.
Single-Track Section Restricts Freight Capacity
The Lötschberg Base Tunnel entered regular service in 2007 and became a central element of Switzerland’s New Rail Link through the Alps. It allows passenger and freight trains to cross the mountain region without using the longer and more energy-intensive historic mountain route.
However, only 14 kilometres of the approximately 35-kilometre tunnel currently support simultaneous traffic in both directions. Trains using the single-track sections must operate within tightly coordinated timetable slots, limiting capacity and reducing flexibility across the wider railway network.
According to the BLS expansion project, the full upgrade will remove this bottleneck and strengthen the north–south rail axis. The additional capacity will be particularly important for freight operators moving cargo between northern and southern Europe.
Main Construction Is Scheduled for 2028
The full expansion is currently estimated to cost approximately CHF 1.7 billion. Major construction work is expected to begin in 2028, with the entire programme lasting around ten years.
BLS says proceeding directly with the full double-track expansion will avoid the eight-month complete closure that would have been necessary under the partial-upgrade option. Rail services are expected to continue operating throughout the construction period.
Once the project is completed, BLS will be able to introduce a permanent 30-minute long-distance service between Bern and the canton of Valais. The additional track capacity will also create more paths for freight trains and improve the reliability and resilience of rail transport across the Alps.
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