Bane NOR is constructing a double track line between Arna and the centre of Bergen. The longest part of the section passes through a tunnel under Mount Ulriken where Bane NOR is constructing a new, parallel tunnel.

The construction of the double track line between Arna and Bergen consists of two projects

Project Arna-Fløen
The project has been in production from 2014 and will be completed in 2022. The main contracts in the project are: New Ulriken tunnel, Arna station and a railway-technical contract.

New Ulriken tunnel
We are constructing a new parallel tunnel between Arna and Fløen. The first 765 meters of the 7.8 kilometers tunnel have been blasted in the conventional manner. This is for the tunnel to be wide enough to accommodate extra passing tracks.

In addition, two diagonal tunnels have been blasted between the old and new tunnel, allowing trains to cross between tunnels. Each of these are 150 meters long. An additional 16 smaller cross-passages will also be blasted between the tunnels for evacuation routes and technical installations.

The remaining 7 kilometres of the new tunnel are excavated with a tunnel boring machine (TBM). The TBM breakthrough was in August 2017.