At the time the railway was variously referred to as the County Line and the Jarlsberg Line, both named for the historic countship of Jarlsberg. By 1874 the state railway commission had considered the line and had concluded that it should be built with narrow gauge. Only its chair, Professor Broch, voted in favor of standard gauge, and at the same time recommended that the Drammen Line be converted to the wider gauge. The advantage of narrow gauge was that it would cut construction costs by a third. By then the railway director, Carl Abraham Pihl, had concluded in disfavor of the Vestfold Line and had instead wanted to prioritize the Østfold Line. His view was shared by the cabinet. The break-through came when plans to extend the line onwards to Skien were launched. Pihl estimated the extension to cost NOK 4.5 million, in addition to a possible branch to Brevik.