A station inside Malmös Citytunneln under construction. Cords for the station lights are hanging from the roof, and machines are working in the background.

The Citytunnel is a transport solution that connects the railway line to the north of Malmö with the railway line to Trelleborg, Ystad and Copenhagen.

NCC’s assignments for the Citytunnel included Malmö C nedre, the new station section at central station. Part of the assignment was a platform that connects the existing railway station to an underground station section directly joined to Malmö C station and a new switchbox, where the two TBM tunnels meet.

The entire project was constructed in an open pit with temporary supporting structures in the form of sheet piles and slotted walls. The work site was 900 meters long in total. Work was divided into phases, since traffic must always be able to pass in a north-south direction.

Approximately 15,000 tons of reinforcement and 120,000 cubic meters of concrete was used in the permanent structures. To ensure that the work was as efficient as possible, about 80 percent of the reinforcing cages were prefabricated indoors and subsequently lifted into place in the pit, where the final work was performed.

Infiltration of groundwater is arranged so that groundwater levels outside the sealing membrane are safeguarded. This is done to minimize settling of buildings and other installations in the immediate surroundings. Excess earth from the pit, approximately 300,000 cubic meters, will be transported to Norra Hamnen harbor in Malmö and be used for filling.