The Oslo Tunnel is a 3,632-metre (2.257 mi), double-track, railway tunnel which runs between Olav Kyrres plass and Oslo Central Station (Oslo S) in Oslo, Norway. The tunnel constitutes the easternmost section of the Drammen Line and runs below the central business district of Oslo. It features the four-track Nationaltheatret Station, Norway's second-busiest railway station, where the Oslo Tunnels lies directly beneath the Common Tunnel of the Oslo Metro. At Frogner, the Elisenberg Station was built, but has never been used. The tunnel is the busiest section of railway line in Norway and serves all west-bound trains from Oslo, including many services of the Oslo Commuter Rail and the Airport Express Train.

Elisenberg station is an unfinished railway station within the Oslo Tunnel on the Drammen Line in Oslo, Norway. The ghost station was partially built during the construction of the tunnel between 1971 and 1980, but has never been put into use. It is located between Nationaltheatret Station and Skøyen Station, at Elisenberg in Frogner. A 220-meter (720 ft) long center platform and part of the access way has been built, but never completed. While the station initially was not put into use because of lack of funds to complete it, it is now unlikely that it will ever be completed, as the need for a station has disappeared and an opening would need a large investment of funds.