The cost of double-tracking and new construction on the Sandbukta – Moss-Sastad section of the Östfold Line has quadrupled from the originally calculated €520 million (NOK 6 billion) in 2017, now reaching €2.15 billion. The main reason is an area of soft clay near Moss that was expected to be smaller and more stable. Following a change of general contractor, the project is now not expected to be completed until 2030, six years later than originally planned. Sensitivity to this geological feature has increased in Norway following a landslide caused by soft clay that killed ten people in Gjerdrum in December 2020.
