The Arna - Bergen stretch is one of Europe’s busiest single track railway lines with 130 trains passing every day.
The stretch is a bottleneck for train traffic to and from the station and the goods terminal in Bergen. The development of a double track between Arna and Bergen consists of two parts: a new tunnel between Arna and Fløen and a double track from Fløen to Bergen with a new signal and safety system.
The new safety system at Bergen station will also have the capacity to control Arna station. In addition, the current tunnel bore will be revamped when the new bore is ready and Arna station will be upgraded and altered.
The new tunnel is first and foremost a measure to increase capacity, allowing passengers more departures to choose from. Two tunnel bores also reduces the vulnerability associated with having only one tunnel bore. For freight traffic there will be an average timetable gain of ten minutes as well as a punctuality gain. This is possible because of direct transport using a separate track for freight trains. For certain freight train departures this could result in a time saving of up to 30 minutes.
The tunnel contract for the new Ulriken tunnel was announced in October 2013 with two alternative driving methods, traditional blasting and the use of a tunnel bore machine (TBM). JV Skanska Strabag and the use of TBM came out on top.