The Albula line between Thusis and Samedan was built between 1898 and 1903. After more than a hundred years, the numerous tunnels are in need of extensive renovation. Several have already been renovated, and the Albula Tunnel, which is over 6 kilometers long, has even been completely rebuilt. The 409-meter-long Bergünerstein Tunnel between Stugl/Stuls and Bergün was reconstructed using the RhB's “standard tunnel construction method,” which was applied by Rhomberg Bahntechnik. While the interior of the tunnel is characterized by concrete elements and a rigid track, the portals had to be preserved in their previous form as far as possible due to the requirements of the Albula-Bernina UNESCO World Heritage Site. The old stones were reused, but the portal was rebuilt with a larger profile, and a few meters inside the tunnel were also bricked up with stones. The G 3/4 # 11 “Heidi” steam locomotive leaves the tunnel on a 3.5% gradient with the Albula steam train 2131 from Filisur to Bergün. The keystone at the top of the portal shows the years 1903 (construction of the tunnel) and 2021 (renovation).
