SBB train in the Hauenstein Basistunnel

SBB to begin 5-year renovation of Hauenstein Base Tunnel

SBB train in the Hauenstein Basistunnel SBB

SBB will be renovating the 8.134-kilometre-long, two-lane Hauenstein Base Tunnel in Switzerland for the upcoming five years to ensure safe rail operations over the next 25 years. This 146.4 million euro project, involving a comprehensive repair of the tunnel vault, renewing or replacing the tracks including rails, sleepers and ballast, and laying new cables, requires SBB to adapt the train traffic timetables. 

The renovations of the Hauenstein Base Tunnel to renew the tunnel vault and the technical systems will start on in September, and continue until autumn 2026. Later on, the tracks will also be renewed, which continues also in several summers after 2026.

The tunnel in Eastern Switzerland was built between 1912 and 1916. In 2019, an average of 320 passenger trains used the tunnel and crossed the Jura mountain range between Tecknau and Olten, each day. The double-track tunnel is part of the Basel-Olten railway line, one of the main axes for Swiss freight and passenger traffic. The last comprehensive renovation work on the tunnel was carried out between 1980 and 1987. Since then, SBB has regularly carried out selective maintenance and renewal work, however, a “major service” is once again needed.

Location of the Hauenstein Base Tunnel in Switzerland (SBB)
Location of the Hauenstein Base Tunnel in Switzerland (SBB)

SBB has been carrying out initial preparatory work in Tecknau since the end of May. In the night from Sunday, 3 September, to Monday, 4 September 2023, the main work for the basic renovation of the Hauenstein Base Tunnel will begin. From then on, SBB will renovate and renew the tunnel vault and the technical installations at night. This part of the work will last until autumn 2026, with interruptions in summer and at the end of the year.

The track drainage is being adapted and improved in certain areas. In addition, SBB is renewing and modernising the tunnel self-rescue devices, which people can use to get to safety in the event of an incident. SBB is also adapting various technical installations, including the ventilation shaft in Zeglingen. In Tecknau and Trimbach, SBB is building a new emergency basin. In the event of incidents in the tunnel, these will be able to retain more wastewater than the existing shaft solutions.

Hauenstein tunnel works
Hauenstein tunnel works

The cost forecast for the project is currently around 140 million Swiss francs (or approximately 146.4 million euros) financed via the performance agreement between the federal government and SBB. The total renovation project is scheduled to end in 2028. In Summer of 2027 SBB will proceed to the renewal of the right tunnel track (seen in the direction of Olten) from Tecknau to the middle of the tunnel. In Summer 2028, SBB will Finnish the renewal of the right tunnel track (seen in the direction of Olten) from the centre of the tunnel to Trimbach.

Major timetable changes

The necessary sectional lane closures will take place from Sunday night to Friday morning and will last from about 10.15 PM. to 5.45 AM. each night. On long-distance services and on the S3 line between Olten-Basel and Delémont, this will lead to earlier departures and longer journey times in some cases. On the S9 line between Olten-Läufelfingen-Sissach, the last two train pairs (Olten from 21.37 and 22.37 / Sissach from 22.05 and 23.05) will be replaced by buses from Sunday to Thursday.

Four tunnel-wide single-track closures are also planned. They will take place in 2024, 2026, 2027 and 2028, in each case for five weeks during the low-frequency summer holiday period. During these closures, SBB will renew the tunnel tracks. Compared to the night-time closures, the tunnel-wide single-track closures substantially reduce the risk of disruption with regard to delayed releases and provisional solutions and shorten the construction time. However, they do result in major timetable changes in long-distance, regional and freight traffic. Buses will run in place of the S9 trains.

No summer closure is possible in 2025, partly because of the five-month total closure of the Laufental line. Total closures are also planned for individual weekends, the next in autumn 2024. During these closures, both tunnel tracks will be closed during the day and at night. SBB will then carry out work on the points or particularly exposed areas in the tunnel. The total closures will cause extensive timetable changes.

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Author: Emma Dailey

Emma Dailey is an editor at and

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