Following the construction of the high-speed Gardermoen Line from Oslo, via Oslo Airport, Gardermoen, to Eidsvoll, the Norwegian Ministry of Transport and Communications started planning additional high-speed lines west and southeast of Oslo.
Setelah pembangunan jalur kereta cepat Gardermobanen dari Oslo, melalui Bandar Udara Oslo, Gardermoen, menuju Eidsvoll, Kementerian Transportasi dan Komunikasi Norwegia mulai merencanakan penambahan jalur kereta cepat ke arah barat dan tenggara Oslo.