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photo of tunnel

Hallandsås Project

On December 8, 2015, the tunnel through Hallandsås was inaugurated and on December 13, 2015, traffic through the tunnel started.

Short intro

The construction of a tunnel through Hallandsås Ridge is part of the West Coast line between Gothenburg and Lund. The tunnel will increase the capacity for passenger and freight traffic, thereby enabling more traffic to be moved from roads to railway.

Why build a tunnel?

Transports are on the rise worldwide, particularly transports by car and lorry. Carbon dioxide is formed when fossil fuels such as petrol are burned, which contributes to the greenhouse effect – one of the major threats of our time to a long-term sustainable society. This increase in traffic has also led to more accidents, so it is imperative that more traffic be moved from roads to railways.


Construction of the tunnel through the Hallandsås Ridge began in 1992. Five years later in 1997, Trafikverket (formerly known as Banverket) and Skanska discontinued construction due to environmental problems. One third of the tunnel had been constructed at the time. In 2001, the Swedish Government and Riksdag decided to resume the project and construction recommenced in 2003.

Geology and natural conditions

At ten kilometres wide and several tens of kilometres long, the Hallandsås Ridge towers above the flat landscape of southern Sweden. The ridge is a bedrock horst, formed by powerful forces millions of years ago. Below the picturesque surface, lies partly cracked and disintegrated rock, with large amounts of water. Building a tunnel under these conditions is a major challenge.

Construction technology

The construction of the tunnel through the Hallandsås Ridge was carried out by approximately 300 people from throughout Europe and a tunnel boring machine named Åsa. To ensure that the tunnel was sealed, a concrete pipe was being built behind the machine. While Åsa bored from the south to the north, the rock in the geologically weak Mölleback zone was being frozen.

Railway installations

Constructing a railway is not merely a matter of laying tracks and installing catenaries. It also requires numerous equipment and system installations. There will, for example, be a large number of communication systems installed. In addition, signal systems for trains and video cameras for monitoring purposes will be installed. Once the installations have been completed, the entire complex will be tested before it can be finally inspected and put into operation.

Environment and control

Implementing a major infrastructure project without affecting the environment is impossible. However, the goal is to minimise the impact. The Hallandsås project has learned from earlier incidents during the tunnel construction and environmental initiatives are now a central part of the construction work. Several internal and external control systems are in place to look after the water, chemicals and ecology.

Safety in the completed tunnel

Railways are a safe method of transport and travelling by train through the tunnel will be just as safe as taking the train in the open. The tunnel opened for railway traffic on December 13, 2015.