Location: Arosa – Switzerland
Start of construction: September 2020
Status: Completed November 2021
Type: Railway tunnel – widening
Length: 299m
Client: Heitkamp Construction Swiss GmbH

The narrow-gauge tunnel of the Rhaetian Railway passes under the Swiss town of Arosa. It forms the entrance to the railroad station of Arosa at an altitude of over 1700 meters.
After the existing tunnel no longer met modern day safety standards, the Rhaetian Railway arranged for it to be improved.

Throughout the course of this work, the profile of the tunnel was widened by demolishing the inner lining and then constructing a new tunnel using the pipe umbrella method. The new inner lining was made of shotcrete. Simultaneously, the track was lowered.

A major challenge in the local area was the undercrossing of two hotel buildings with a low tunnel coverage.