Lötschberg tunnel

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Lötschberg tunnel (apex tunnel)
Lötschberg tunnel (apex tunnel)
Location of the Lötschberg tunnel
use Railway tunnel
place from Kandersteg to Goppenstein
length 14,612 mdep1
Number of tubes 1 (2-track)
start of building March 7, 1907
completion June 3, 1913
operator BLS AG
release July 15, 1913
Lötschberg tunnel (Switzerland)
Red pog.svg
Red pog.svg
North portal 617529  /  147469
South portal 624274  /  135428
South portal of the Lötschberg tunnel in Goppenstein
North portal in Kandersteg

The Lötschberg tunnel is a 14.6 km long railway tunnel opened in 1913 by BLS Netz AG from Kandersteg to Goppenstein in Switzerland . It is a single-tube, double-track tunnel and the heart of the Lötschberg mountain route from Spiez to Brig in the Swiss canton of Valais .


As the largest structure on the Lötschberg line, a tunnel was to connect the Kandertal with the Valais . The project manager Wilhelm Teuscher studied different ways to go under the 3500 m high Alps. The variants envisaged a 7 km long apex tunnel in the Gastern valley and two longer tunnels from the Kander plateau into the Lötschental. Finally, the "variant D" from Kandersteg to Goppenstein with a 13,725 m long tunnel and a straight tunnel axis under the Balmhorn massif was chosen. The tunnel was originally planned to be single-lane with an alternative station for train crossings of 500 m in length in the center of the tunnel.

The first triangulation measurement of the tunnel axis was carried out on July 14, 1906 . It was repeated and completed by Prof. Baeschlin on October 1st, after the first surveyor died unexpectedly. The construction of the tunnel was entrusted to the Entreprise Générale du Lötschberg (EGL) construction consortium .


Outline map of the Lötschbergbahn between Spiez and Brig in Switzerland, showing the part from Frutigen to Brig. Note the double loop completed with a 270 degree spiral tunnel between Kandergrund and Felsenburg (approx. Km 60 and 70) and the straight stretch of the Lötschberg tunnel between km 75 and 90.
Location of the Lötschberg tunnel between km 75 and 90: Originally planned straight route and implemented bypass, route positions here in km from Bern.

start of building

On October 15, 1906, work began with the removal of rock debris in front of the future north portal of the tunnel. Construction work on the tunnel itself began in Goppenstein on November 1st, and one day later also on the north side near Kandersteg. Initially, the tunnel was worked by hand with modest means. Mechanical hammer drills arrived in Kandersteg in January 1907 and were used from March 7th. In the south, delivery of the rotary hammers took a few months longer and the mechanical drilling did not begin there until April 9, 1908. Part of the reason for this delay was, among other things, delays in the construction of the two operating lines from Frutigen and Naters up to the tunnel portals. The rotary hammers and the tunnel locomotives were operated with compressed air. The main tunnel was 3.5 meters wide: 17 to 20 miners worked on the tunnel front in eight-hour shifts, seven days a week. The drilling was only briefly interrupted during the Easter and Christmas holidays.

In August 1907, a federal subsidy was approved for the double-lane expansion of the tunnel and the clearance profile increased to 8.8 meters. At the beginning of 1908, around 1,700 people were working on the tunnel, the majority of whom were guest workers of Italian origin. The roughly 220 engineers and foremen were mostly Swiss and French. Most of them had already gained experience in similar large-scale projects all over the world and some came there directly from the construction of the Simplon Tunnel .


On February 29, 1908, after days of snowfall, an avalanche fell on the south side and buried the workers' accommodation. 25 people were killed.

On July 23, 1908 at 2:30 a.m., at kilometer 2.674, a blast into the soft rock of the Gastern valley expected 100 meters further up took place . Immediately about 7000 cubic meters of sand, gravel and mud penetrated 1.5 kilometers into the tunnel and buried everything on their way. 26 workers were buried and killed. Only the body of Vincenzo Aveni was found and buried on behalf of all his comrades in the Kandersteg cemetery. In the Gastern Valley, the terrain was lowered to a depth of 3 m.

During the investigation into the accident, EGL decided to resume construction work. Initially, it was planned to keep the original, straight propulsion axis after this accident as well. The penetration into the buried tunnels was tried several times, but was prevented by rubble sliding down again and again. The tunnel consortium then stopped its work until the BLS management approved a bypass. On August 4, 1908, the old tunnel was bricked up by EGL, leaving the 25 corpses of the Italian miners in the mountain forever.

In December 1908, the Federal Council approved the construction of the bypass tunnel with the resulting curved lines of the tunnel. The tunneling work was resumed on February 15, 1909. Thanks to the new tunnel, the Gastern Valley was driven under without any problems at kilometer 5.1 and the tunnel was lengthened by 807 meters. This resulted in a new total length of the Lötschberg tunnel of 14,612 meters.

On January 20, 1910, an avalanche that fell annually, the Rücklaui , blocked the south portal of the tunnel. An opening had to be dug in the mass of snow in order to be able to get out the 30 miners remaining in the tunnel. The two portals were subsequently to protect against falling rocks and avalanches with enclosures extended by 15 meters on the north side and 55 meters on the south side.


On March 31, 1911, a hammer drill on the south side pierced the last, approx. 80 cm thick separating wall. The hole was enlarged with hand drills and the two engineers shook hands. To compensate, the miners on the north side were allowed to detonate the final blast. Twelve dynamite sticks broke through the dividing wall at 3:55 a.m. at 7367.29 meters from the north portal and 7237.80 meters from the south portal.

In spite of the bypass tunnel, the difference at the meeting in the opposite site was only 25.7 cm horizontally and 10.2 cm in height. The excavation work was completed on March 31, 1912. The construction workers and machines were then used again for the two tunnels of the Mont-d'Or tunnel and the Grenchenberg tunnel .


The rails for the standard gauge were laid from July 20, 1912 and were continuously passable on September 28 for the initially single-lane track. After the completion of the two-train track and the installation of the contact wire lines , the first electric locomotive drove through the tunnel on June 3, 1913 . Three days later, the federal authorities accepted the tunnel and issued the operating license. On July 15, 1913, the Lötschberg line was opened to public transport.


From 2018 to the end of 2022, the superstructure in the tunnel will be renewed for 105 million francs and a slab track installed. The restructuring costs of Marti AG have now risen to CHF 157 million. The illegal disposal of 200 tons of concrete sludge led to an environmental scandal in the Blausee-Mitholz quarry .


  • Length: 14,612 meters
  • North portal height: 1200 m above sea level M.
  • Height of the south portal: 1216 m above sea level M.
  • Peak: 1239.54 m above sea level M.
  • Slope north side: 5390 m = 7 ‰; 1690 m = 3 ‰
  • Slope south side: 4328 m = 3.8 ‰; 2819 m = 2.415 ‰
  • Inclination of the middle of the tunnel: 308 m = 0 ‰

Sources and Literature

Web links

Commons : Lötschberg rail tunnel  - collection of images, videos and audio files

Individual evidence

  1. BLS AG - RegioExpress Lötschberger. In: www.bls.ch. Retrieved May 29, 2016 .
  2. Lötschberg tunnel. In: Viktor von Röll (Ed.): Encyclopedia of the Railway System . 2nd Edition. Volume 2: Building Design - Brazil . Urban & Schwarzenberg, Berlin / Vienna 1912, p.  256 .
  3. ^ Ascanio Schneider and Armin Masé: Disasters on rails. Railway accidents, their causes and consequences . Zurich 1968, p. 287.
  4. BLS starts the first intensive construction phase in the Lötschberg summit tunnel. In: bls.ch. October 18, 2018, accessed January 26, 2020 .
  5. BLS starts the second intensive construction phase in the Lötschberg summit tunnel. In: bls.ch. BLS AG, October 21, 2019, accessed on January 26, 2020 .
  6. Cost increase in renovation - Lötschberg tunnel: Director of the Federal Office of Transport ruffles BLS. In: srf.ch . October 14, 2020, accessed October 14, 2020 .
  7. environmental scandal Blausee - Even concrete slurry illegally dumped in the quarry Blausee-Mitholz. In: srf.ch. February 11, 2021, accessed February 11, 2021 .