It constitutes part of the Vestfold Line, owned by the Norwegian National Rail Administration.

[3] The original railway line past Smørstein opened on 13 October 1881,[2] following a route which ran closer to the fjord.

[4] In August 1918 the Norwegian State Railways (NSB) was working on building a level crossing at Smørstein as part of a realignment of a road.

The smaller slides continued and in the morning of 19 August the land under the tracks had slid away, leaving the rails hanging in mid-air over a distance of 70 meters (230 ft).

[4] When the slides finally had concluded after a month, nearly 30,000 cubic meters (1,100,000 cu ft) of earth had slid into the fjord.

The shipping company Westergaard & Co was hired and they operated Færder, capable of 200 passengers, which ran between Framnæs and Bogen.

Later the ferry SS Bastø 1 was hired, allowing an entire train load to be carried in one sailing.

The geological surveys were led by Professor Brøgger, who concluded that the slide was caused by faults in the fjord.

[2] Construction then continued with the building of a tunnel, as the ground was considered too unstable to support railways.