sentences:  The Grorud Line was connected on 16 October 1966, the Østensjø Line on 29 October 1967, and the Furuset Line on 18 November 1970.During the 1960s, the Drammen Line was being planned to connect to Oslo East Station through the proposed Oslo Tunnel.This would make Oslo West Station unnecessary, and would allow a central station to be built at the location of the East Station.