Oslo Central was built on the site of the older Oslo East Station (Oslo Østbanestasjon, Oslo Ø), the combining of the former east and west stations being made possible by the opening of the Oslo Tunnel. Oslo Central has nineteen tracks, thirteen of which have connections through the Oslo Tunnel. The station has two buildings, the original Oslo East building and the newer main building for Oslo Central. Each building houses a large shopping centre. The square in front of the station is called Jernbanetorget.
When the first railway line, Hoved Line, was built between Oslo and Eidsvoll in 1854, the terminus in Oslo was constructed as an ad-hoc solution located at Gamlebyen. Alternate sites included Youngstorget, Grünerløkka and Vaterland Bridge. In 1852 an architectural competition was held, and a plan based on Crown Street Station in Liverpool won. The station was located east of the river Akerselva, but could not serve as a permanent solution, as it was close to neither the city centre nor the port. In 1859 the freight section of the station was expanded with the purchase of land between Loelva and the port, and part of Bjørvika. From the beginning, rail traffic increased, especially after the expansion of the Trunk Line to Hamar in 1862, and the opening of the Kongsvinger Line in 1865.
In 1872 Oslo got its second terminal station, located at Pipervika near Aker Brygge and the city hall. Oslo West Station (or Oslo V) was built to allow the then narrow-gauged Drammen Line between Drammen and Oslo to terminate in downtown Oslo. The two stations were located about 2 km apart and were not connected by rail until 1907 when the Oslo Port Line was built. There had been discussions about building a central station to connect the Drammen Line with the eastern station, but this idea involved building it via Majorstuen and Grefsen. Oslo V always remained a secondary railway station in Oslo, since it mostly served local traffic to Buskerud, Telemark and Vestfold in addition to the Sørland Line.
The year after the western station opened, in 1873, the Norwegian legislature, the Storting, decided to build a new railway from Kornsjø at the Swedish border through Østfold to Oslo, the Smaalenene Line (now the Østfold Line). Traffic at the station was expected to explode due to this railway and it was decided that a new station had to be built. The engineers within NSB wanted to locate this new station west of the river Akerselva, between Jernbanetorget and Bjørvika. But a conflict arose between Carl Abraham Pihl, who was director of NSB at the time, and the City of Oslo. While Pihl wanted a separate station for the Smaalenene Line, the city wanted to concentrate the stations in one place in Oslo. The engineers insisted on moving the station closer to the city. The architect Georg Andreas Bull drafted four plans for a new station with nine tracks over the river Akerselva. In 1878 the legislature decided to build the smallest suggested station—with only seven tracks over the river, claiming that the station was oversized. Oslo East Station (Oslo Østbanestasjon, Oslo Ø) opened in 1882.
But it was soon recognized that the station was too small. The population of Oslo doubled to 150,000 between 1875 and 1890 and from the opening of the station to 1890, the traffic increased from 400,000 passengers annually to more than a million. The most critical part was the freight section, where the trains had to partially use the main railway for switching. One of the proposed solutions was to build the line from Østfold on a viaduct into the station and elevate it on a level above the other tracks. Another problem arose in 1893, when it had to be decided where the new Gjøvik Line was to terminate. Some suggested a station at Grefsen with one line to Oslo East and one via Majorstuen to Oslo West. The Storting decided in 1895 that the Gjøvik Line was to be built to Oslo East.