The tunnel was excavated using a pioneering method in the country, with four double-shield tunnel boring machines (TBMs) simultaneously drilling and starting from the same point, in conjunction with traditional drilling and blasting methods.
The contract consists of a four-lane highway covering a total of 23 km, eight of which will be underground, with four tunnels between one and four kilometres long. The route, which also includes eight bridges, will partly follow the old road, with the exception of the tunnels which will run parallel to the existing ones.This new infrastructure will widen the route from two to four lanes, improving mobility in the northern part of Trøndelag County.
The contract includes the design and construction of a 10.3 km, twin-track line, some of which will run above ground. The new line also requires the JV to build two tunnels, each longer than 2 km (Moss Tunnel and Carlberg Tunnel), two shorter cut-and-cover sections, a tunnel portal and a new train station with 800 m-long platforms and a pedestrian bridge. The project is part of the Bane NOR Intercity programme to develop connections between the country’s main cities and relieve congestion around the capital city of Oslo.