Follo Line High-Speed Rail Tunnels

The Follo Line tunnels are Norway's biggest railway project. The contract includes the design and construction, under an EPC, of twin tunnels of 8.8m internal diameter, drilled by four tunnel boring machines, each 19.5km long. 

Once completed, the twin tunnels, designed for trains traveling at speeds of up to 250 km/h, will be the longest rail tunnels in Scandinavia. They are being excavated by four huge, double shield tunnel boring machines (TBMs).

The work consists of the largest, and second largest, of four EPC turnkey contracts included in the Follo Line project, Norway’s biggest transport infrastructure project to date.

The TBMs started work halfway through the section, where the facilities serving the casting and concrete plants are located. Access to this area, where an escape tunnel and two caverns for the assembly of the TBMs have been installed, is through a series of drilled and blasted tunnels. The 40cm-thick lining of the tunnels is made up of almost 20,300 pre-fabricated rings, each comprising 7 segments.

OBJECTIVE: Connect the cities of Oslo and Ski, forming a central axis of interurban development south of the Norwegian capital

BENEFIT: Drive the economic development of the region

MILESTONE: Scandinavia’s longest rail tunnels