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    Follo Line Railway Tunnels

    The largest railway project in Norway


    The contract includes the design and construction, through an EPC, of twin tunnels with an internal diameter of 8.75 m, performed with 4 tunnelling machines, each measuring 19,5 km long.

    Once completed, the twin tunnels – designed for trains reaching up to 250km/h – will be the longest railway tunnels in Scandinavia.

    The tunnels are each 19,5 km long and have an internal diameter of 8.80 m. They have been dug into the rock by four double shield tunnelling machines.

    This is the second and largest of the four EPC (turnkey) contracts included in the Follo Line project, the largest infrastructure project in Norway so far.

    The works performed with the tunnelling machines start in the middle of the route, where the facilities serving the keystones and concrete plants are located. Access to this area, where a rescue area and two caverns for the assembly of the tunnelling machines have been installed, is carried out through a series of tunnels built by digging and blasting. The tunnel’s lining is composed of around 20,300 prefabricated rings, with seven keystones each, measuring 40 cm thick.


    Design, assembly and use of tunnel boring machines to build our future world


    To link the cities of Oslo and Ski, creating the backbone of intercity development towards the south of the Norwegian capital.


    Promoting economic development in the region


    The longest railway tunnels in Scandinavia

    General Information

    Oslo. Norway
    Contract type
    Design and Construction in EPC mode
    Two twin tunnels, each measuring 19,5 km long, with an internal diameter of 8.75 m, dug into the rock using four double shield tunnelling machines.
    Year of project completion

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