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.^[6] 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.^[7][8]

In 1994, early drilling was conducted in the area.^[6] During 1999, full-scale construction work on the LBT commenced.^[9][10] 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.^[9] The remaining 20% was excavated using tunnel boring machines (TBMs). The excavation work was conducted from both the north and south portals.^[9] During April 2005, the construction process reached a milestone when breakthrough was achieved; the event was attended by 1,000 guests.^[6] The excavation process reportedly used 15 thousand kilograms (16 short tons) of explosives, while the material extracted would have filled a freight train that was 4,000 kilometres (2,500 mi) in length.^[6] Work over the following year centered on the fitting-out process, installing all of the operational systems, including the track itself.^[9]

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.^[11][12][13] The LBT overran its budget of roughly $2.7 billion by around $840 million, which has impacted its operation.^[6]

On 9 December 2007, the LBT was declared operational.^[14] 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 300 m (980 ft) with cross cuts, enabling the other tunnel to be used for escape.^[15]

Currently, from South to North, a third of the tunnel is double track, a third is single track with the second bore in place but not equipped, and a third is only a single track tunnel with the parallel exploration adit providing the emergency egress. This unused western bore has been used by maintenance crews as a means of accessing the active eastern tunnel; an adjacent exploratory bore driven during the early 1990s has also proved useful for such purposes.^[9]

The construction process was divided into three phases, of which only phase one has been completed to date:

• Phase one: construction of about 75% of the length of the West tube and the complete East tube of the main tunnel, the Engstlige tunnel, the two bridges across the Rhône, and the branch bore from Steg. Tracks are laid in the Eastern tubes of the LBT and Engstlige tunnels, and for some 12 km (7.5 mi) in the western tube of LBT, starting from the South.
• Phase two: laying of tracks in the bored but not equipped part of the western tube of LBT, and in the western tube of Engstlige tunnel.
• Phase three: construction of the remaining 8 km (5.0 mi) of the western tube, laying tracks on the Steg branch, and connection of this branch to the main line Brig-Lausanne, but towards Lausanne.

Phases two and three may be performed concurrently or separately. The cost of completing work on the LBT has been estimated to be around one billion Swiss francs.^[16] The project also includes two parallel bridges over the river Rhône in canton Valais, the 2.6 km (1.6 mi) Engstlige tunnel (built with cut-and-cover method; the two tracks are separated by a wall). A planning contract for phases two and three was awarded in 2016 to the Swiss engineering consortium IG Valbt, headed by SRP Ingenieur.^[16] The resulting plan was presented for review in early 2019,^[9] and a decision between funding only Phase two or both Phase two and three is expected in 2023. The first option is naturally cheaper and is two years faster, but it provides a much lower capacity and requires an eight months full closure of the line.^[3]