The Grätli tunnel is located in the upper section of the historic Schynige Platte Railway (SPB), between kilometres 5.9 and 6.0. The rocks near the tunnel have always been in motion. The tunnel was last extensively renovated in 2014. The tunnel has been monitored with measuring devices since August 2023. Damage that occurred in the course of 2024 required stabilisation measures, which were carried out in January/February 2025.

Further stabilisation measures required

During this work, it became clear that further measures would be necessary as the extent of the damage turned out to be greater than anticipated. According to experts, rock movement may accelerate again due to melting snow and warmer temperatures.

Further stabilisation work will therefore be carried out in May 2025. A vaulted arch with steel girders will be installed for this purpose. The tracks and overhead lines have to be removed and then reinstalled later. The preparatory work will start in April. A monitoring concept for the tunnel is also being established to ensure continuous monitoring during the works and safe operations throughout the summer.

The costs of these stabilisation measures will amount to around CHF 350,000. The work is expected to take around five weeks so that the Schynige Platte Railway can start its season as planned on Saturday, 14 June 2025.

Construction work before and after the season

Since spring 2023, long-term work on the Schynige Platte railway track has been underway. Renovation and maintenance work is carried out before the start and after the end of the season. A total of eleven stages are planned.