The Vestfold Line is part of the Intercity Triangle, which the authorities wish to prioritize for future upgrades. The long-term goal is to construct a continuous high-speed double track from Oslo to Skien. This is in part a response to the E18 being upgraded to a motorway. In addition to increased speeds, the current line does not allow for more trains to operate. Plans call for an initial construction of the Inner Intercity Triangle, which will give continual double track from Tønsberg to Oslo, in addition to the shortening of the segment between Larvik and Porsgrunn. This will allow travel time from Tønsberg to Oslo to be reduced from 1 hour and 28 minutes to 1 hour. An upgrade of the rest of the line, scheduled for completion by 2030, will cut travel time from Porsgrunn to Oslo from 2 hours and 45 minutes to 1 hour and 36 minutes. The line could accommodate an estimated 9.5 million passengers per year, and each station could receive between 100 and 500 percent increase in patronage. Despite the plans for the upgrades of the Vestfold Line, there are no current plans for upgrading the line and tunnel between Asker and Drammen, which all trains must follow to Oslo and which has a maximum speed of .