Follo Line – Behind the project
The Follo Line is a highspeed railway line that connects the capital of Norway (Oslo) and the township of Ski. The complete line is 22 km long, exists out of 20 km of tunnel and is split in six major EPC contracts commissioned by the Norwegian National Railway Administration (Jernbaneverket). Most of the line, 19 km, will be a double bored TBM tunnel which will be the longest railway tunnels in Norway.
The Follo Line will be running parallel to the Østfold Line and is engineered for 250 km/h (155 mph). It will increase the capacity from 12 to 40 trains per hour along the South Corridor. Local and freight trains will use the Østfold Line, while regional and express trains will use the Follo Line. Travel time will reduce from 22 to 11 minutes.
Norway’s longest railway tunnel project
Construction started in 2014 and is planned to be completed by 2020/2021. The line will cost over 26 billion Norwegian Krone (NOK) which is around 2,6 billion euro. The main six EPC contracts are the following:
- D&B access
- D&B escape tunnel
- TBM excavation 4 drives
- Cross passages
- Track and systems
The total duration of the project was estimated at 78 months which is around six and a half years of work. The EPC TBM excavation contract, which is the biggest contract, was won in 2015 by the Acciona Infraestructuras S.A. and Ghella S.p.A. Joint venture (AGJV) and will be completed in October 2021 with a contract value of 1 billion euro.
To complete this contract, they excavated two parallel tunnels of 20 km each, one for the southbound trains and one for the northbound trains. Each tunnel has been excavated by two TBM’s resulting in 4 TBM drives. Dramix 4D 65/35BG was used for the TBM excavation contract.
A combined reinforcement solution for tunnel lining segments was used, resulting in segments with an outer diameter of 9.55 mm, an inner diameter of 8.75 m and a thickness of 400 mm. They used around 500.000 m³ of concrete with a total fibre volume of app. 10’000 tons.
They estimate that the Follo Line will be completed in 2020-2021. The new line is predicted to increase rush hour rail ridership by 63% and increased freight on rail would remove 750 trucks daily from European Route E18.