The Lötschberg Base Tunnel (LBT) is a railway base tunnel on the BLS AG's Lötschberg line cutting through the Bernese Alps of Switzerland some below the existing Lötschberg Tunnel. It runs between Frutigen, Berne, and Raron, Valais.
The Lötschberg Base Tunnel was built as one of the two centrepieces of the NRLA project (the New Railway Link through the Alps). Construction of the LBT commenced in 1999 and achieved breakthrough during 2005. A ceremony to mark its completion was held in June 2007; the first train operations began in December 2007. Within only a few years of opening, the LBT had become saturated because of a single-track section present; without the completion of the second bore, its overall capacity has been greatly reduced. During 2016, a planning contract was awarded for the completion of the second track of the LBT, which has been estimated to cost 1 billion Swiss francs. The resulting plan was presented in Spring 2019. A decision between a full or partial completion of the second tube of the Lötschberg Base Tunnel is expected in 2023.
Construction
Initial construction
The LBT was principally constructed to ease lorry traffic on the Swiss road network by providing faster routes for rail-based freight as an alternative. Reportedly, between the 1980s and 2000s, traffic on the north-south European axis (North Sea Ports to/from Northern Italy and along the Blue Banana) had increased more than tenfold, necessitating infrastructure investments to better cope with rising demands. Accordingly, the LBT allows a substantial number of trucks and trailers to be loaded onto trains in Germany, pass through Switzerland on rail and be unloaded in Italy (rolling highway or trailer-on-flatcar respectively). It also cuts down travel time for German tourists going to Swiss ski resorts, and puts the Valais into commuting distance to Bern by reducing travel time by 50%. The total cost was SFr 4.3 billion (as of 2007, corrected to 1998 prices). This and the Gotthard Base Tunnel are the two centerpieces of the Swiss NRLA project.
In 1994, early drilling was conducted in the area. During 1999, full-scale construction work on the LBT commenced. It was largely excavated using a combination of traditional techniques, including drilling and blasting. Roughly 80% of the tunnel was built using these conventional practices. The remaining 20% was excavated using tunnel boring machines (TBMs). The excavation work was conducted from both the north and south portals. During April 2005, the construction process reached a milestone when breakthrough was achieved; the event was attended by 1,000 guests. The excavation process reportedly used of explosives, while the material extracted would have filled a freight train that was in length. Work over the following year centered on the fitting-out process, installing all of the operational systems, including the track itself.
In July 2006, track construction in the LBT was declared complete. Extensive testing then took place, including more than 1,000 test runs, which focused among other things on the use of the ETCS Level 2 system. Once satisfied that all systems had been validated, an official opening ceremony for the LBT was held during June 2007; at this event, the tunnel was recognised as the longest land tunnel anywhere in the world. The LBT overran its budget of roughly $2.7 billion by around $840 million, which has impacted its operation.
On 9 December 2007, the LBT was declared operational. Initially, only regular freight services traversed the LBT, along with a minority of international and InterCity passenger trains (without stops between Spiez and Brig); passenger trains continued to operate on the old timetable (the travel time between Spiez and Brig was considered to be 56 minutes until December 2007, even if actual travel time through the LBT was only about 30 minutes). Since February 2008, the LBT has been routinely used for normal InterCity routes. Travel time between Visp and Spiez is about 28 minutes, of which 16 minutes is spent inside the LBT.
Additional phases
As a consequence of spiraling costs attributable to the overall NRLA project, it was decided to redirect funds from the Lötschberg tunnel to the Gotthard Base Tunnel. This funding decision leaves the LBT in a partially-completed state for a protracted period. Once fully complete, the LBT will consist of two single track bores side by side from portal to portal, connected about every with cross cuts, enabling the other tunnel to be used for escape.