The segment to Bjerka Station opened on 21 February 1942. The section onward to Finneidfoss could not be opened due to a slide in a cutting north of Bjerka, caused by erroneous earth-moving techniques. To reach Mo i Rana a temporary segment was opened past Bjerka Tunnel, allowing the final part to Mo to open on 21 March. The station was far from finished. The missing to connect to the Dunderland Line were quickly built, opening on 5 May. The poor condition of the track meant that travel time on the from Mosjøen to Mo was three hours. Much of the work on this section had to be corrected and improved afterwards. An estimated 18 workers were killed on this segment alone.