Introduced in 1952, shepherding the plans through the Storting proved difficult. In 1959 the plans were again revised and in 1960 a new committee was created, which suggested building a third line between Grefsen and Bestun for freight trains to connect between the eastern and western lines. It also felt that the tunnel should be expanded westward and terminate somewhere between Skarpsno and Skøyen and at the same time close the Oslo Port Line. The new plans were approved by the Storting in 1962.