The Kolsås Line is a 12.1-kilometer (7.5 mi) line of the Oslo Metro. It branches off from the Røa Line at Smestad Station and runs through western Oslo and Bærum to Kolsås Station. It serves the neighborhoods of Ullernåsen, Øraker, Jar, Bekkestua, Haslum, Gjettum and Kolsås. It is served by Line 3 of the metro at a 15-minute headway. The section from Jar to Bekkestua is built as a dual system with overhead wires, allowing Line 13 of the Oslo Tramway to continue from the Lilleaker Line to Bekkestua every ten minutes.

The Oslo tram network is the tram system in Oslo, Norway. It consists of six lines with 99 stops and has a daily ridership of 132,000. It is operated by Sporveien Trikken AS, a subsidiary of the municipally-owned Sporveien who maintain the track and 72 tram vehicles on contracts with the public transport authority Ruter. The system operates on standard gauge and uses 750 V DC overhead. Depot, workshops and headquarters are at Grefsen. There is also a depot at Holtet that is home to the technical company InfraPartner, which maintains the track for the tram and metro systems in Oslo, and a small office building for Oslo Sporveier.