The Lötschberg Base Tunnel in Switzerland, which is part of the New Railway Link through the Alps (NRLA – NEAT) and on BLS AG’s Lötschberg Line, suffered water and sand ingress on 13 March 2020 and has been closed ever since. On Friday 24 April 2020 the tunnel will open again to railway traffic.
At 5pm on Friday, 24 April, BLS will open the second tube of the Lötschberg Base Tunnel to railway traffic. The eastern tube had to be closed as a result of the water and sand ingress that occurred on 13 March but the clean-up works have now been completed. BLS suctioned off and removed the sand and flushed out the sewage pipes. BLS also cleaned out the tunnel interior.
However, BLS must control the situation long-term and is consequently developing a number of measures. It is examining different approaches, all of which have the aim of creating capturing capacity so that any solid material is deposited and can be cleared away without affecting railway traffic should there be future events. BLS estimates it will have developed a plan by autumn 2020, which it will then submit to the Federal Office for Transport (BAV) to achieve planning approval.
Monitoring
In order to secure the affected location over the medium-term, BLS has fitted temporary steel tanks in the eastern tube and is monitoring the site with cameras. Experts are also regularly inspecting the tunnel. This will allow BLS to act immediately should there be a further instance of water and sand ingress, halting railway traffic if necessary.
The first instance of sand and water ingress in the Lötschberg Base Tunnel occurred on 6 February 2020. The exact location was between Ferden and St. German. The event on 13 March occurred at the same location but with more sand. The previously installed tanks could not capture the material. the affected location of the tunnel is situated in a water-permeable chalk bed with karst structures. Alterations to the hydrological balance inside the mountain cannot be predicted.
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