 The Sinsen Line opened on 1 February 1923 as a branch of the Rodeløkka Line , which continued along Trondheimsveien to Carl Berners plass . The entire Rodeløkka Line was rebuilt with double track in 1938 . In December 1940 , a service extension of the Rodeløkka Line was built from Rodeløkka to Søndre Åsen , operated by the Oslo trolleybus , remaining in service until 14 January 1945 . The tram service on the Rodeløkka Line was terminated on 6 February 1949 , and replaced with bus line 27 , although the tracks were kept . 
