Work north of Mosjøen, on the section to Elsfjord, started in 1935, based on a detailed plan approved by Parliament the same year. Proposals were made for the line running on either side of Elsfjorden, with the east side ultimately chosen. A major dispute on this segment was if the line should cross the fjord along Røssingtangen and on a bridge, but instead a longer route around the fjord was chosen. Elsfjord Station was completed in 1938 to be used as a construction office. The Wehrmacht intensified construction on this section from 1940, and by July 1,950 people were working there, increasing to 4,966 people by September. Attempts were made to introduce work on Sundays, but this proved impossible to carry out as the workers just became tired. Futsa was crossed using a German-built bridge. A major hindrance to faster completion was the time needed to blast the final four tunnels. Temporary operation on the line to Elsfjord commenced on 15 March 1941. Without a rail or road connection onward, there was little practical use of this segment on itself.