MX3000 is an electric train used on Oslo Metro in Oslo, Norway. The multiple units are produced by Siemens Mobility, who started serial delivery in 2007. Seventy-eight three-car units were ordered by Sporveien, and five by Akershus County Municipality. They replaced the older T1000 and T1300 stock that was used on the Oslo Metro since 1966. By 2010, the last T1000 and T1300 trains had been retired and replaced by 83 three-car units. 32 additional sets were ordered, and the final train set was delivered in 2014, increasing the fleet to 115 units.

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.