The renewal of the initial total of 80km may be followed by another stretch of 8km in each direction.
Strukton Rail will use its equipment to renew the rails, sleepers and ballast.
The project runs between the villages of Boden and Bastuträsk in the northernmost area of Sweden and will be carried out in three stages. The first stage will start as early as next month and the entire project is scheduled for completion in October 2017.
The line involved is the main railway through Upper Norrland, served primarily by freight trains. It provides a key route for the mining and forestry industry in northern Sweden. In recent years, the stretch has been regularly affected by broken rails and other incidents that can be linked deterioration. This has resulted in reduced capacity and reduced speed limits for some time.
Original plans to renew the tracks between Constance and Bastuträsk were postponed for a budget vote in Swedish parliament in 2015. This decision was however reconsidered, and a new plan was formulated to replace rails and sleepers and clean the ballast on a total of 100km of track.