Twin tunnels, each 19.5km long with an inside diameter of 8.8 meters, will connect the cities of Oslo and Ski, establishing a central axis for interurban development to the south of the Norwegian capital.
Designed for trains traveling at 250km/h, connecting the inhabitants of the two cities, the tunnels are being excavated simultaneously by four huge, double shield tunnel boring machines (TBMs).
These have begun drilling through the hard rock of the Ekeberg hills in Åsland, halfway along the route. Facilities have been installed to serve the casting and concrete plants. Each of the TBMs measures 150m long and weighs 2,400 tonnes.
The tunnel drilling project also includes blasting of caverns to house the TBMs, an escape tunnel 2.7km long and two 420m transport tunnels. The consortium, made up by ACCIONA Infrastructure and Ghella, will also carry out the installation of the railway up to the signalling systems.
Connect the cities of Oslo and Ski by rail, forming a central axis for interurban development south of the Norwegian capital.
Drive the economic development of the region and connect the inhabitants of Oslo and Ski.
Once complete, the two 19.5km rail tunnels will be the longest in Scandinavia.