Follo High-Speed Railway Line, Oslo, Norway

Follo Line is a planned 22.5km (14mi) high-speed railway line between Norway's capital city Oslo and the suburban town of Ski. The double-track line will run parallel to the Østfold Line.

Construction on the new line is expected to begin in 2014 and be completed by 2020. The Norwegian National Rail Administration (NNRA) will own the line. Norwegian State Railways (NSB) will operate trains at a maximum speed of 250km/h on the new line.

Upon completion in 2020, the line will serve about 150,000 passengers each day. The estimated cost of the project is about NOK 11bn ($1.9bn).

Oslo-Ski high speed rail line

The Norwegian Parliament decided to build a high-speed rail line between Oslo and Eidsvoll, via the new Oslo Airport, Gardermoen, in 1992.

The Follo Line project was conceived by the Norwegian National Rail Administration (NNRA) as part of the plan to build four tracks along the three main corridors out of Oslo. The three main corridors include the Gardermoen Line, which was completed in 1998, the Asker Line, which was opened in 2005 and extended in 2011, and the Østfold Line, which was opened in 1879 and later upgraded to a double-track line and operated at higher speeds between Ski and Moss.

In order to upgrade the rest of Østfold Line to high-speed, the track capacity through Oslo and Ski needs to be increased. The line between Oslo and Ski restrains the track to 12 trains an hour and also hampers the freight trains traffic during the rush hours. The travel time for direct trains to Ski is 22 minutes, while commuter trains take 31 minutes.

Initial plans for the Follo Line were made in 1995. The new line, to be laid between Oslo and Ski, is expected to increase the rush hour rail ridership by 63% and also significantly increase the freight on rail. It will also decrease the travel time on express and regional trains from Ski to Oslo by half, from 22 to 11 minutes.

The line will reduce 5,800 car journeys a day, remove 750 trucks daily from European Route E18 and in turn eliminate 5,500t of CO2 emissions a year. Once the new line is open, all the local trains will be restricted to the Østfold Line and faster trains will be used on the new double-track line.

Follo line high-speed infrastructure

The new double-track line will run 19km through a single tunnel. The Ski station will be expanded to include new platforms and six tracks, as part of the project.

The NNRA plans to construct new storage tracks before building the public areas. Construction at the Ski station will include laying 50km of cable for reconstruction work, raising and extending all the platforms and improving the transfer areas inside the station.

The tunnel will be constructed using drill and blast methods by deploying two tunnel boring machines (TBMs). The tunnel will have two separate tubes with cross-connections for every 500m. It is estimated that about 4.5 million cubic metres of rock and 7.2 million cubic metres of muck will be excavated during the tunnel's earth works.

The course of the new line will be finalised at the end of 2012 after the completion of the impact study and public hearing process by the respective municipalities. The external quality assurance will be completed in 2013 and construction on the new line will start in 2014.

Follo Line rolling stock and contracts

The Norwegian rail company NSB will take the delivery of the new trains to be run along the Follo Line in 2012.

In September 2011 Atkins, in partnership with Norwegian engineering consultancy Aas Jakobsen, was awarded a contract to design new signalling systems for the railway line.