If it met performance expectations, future orders could be made to replace the T1000 stock when the latter reached the end of its economical life in around 2000.

[1] On 22 October 1987, a fatal accident occurred when one of the old HkB 600 units suffered a catastrophic failure of its braking system, and rolled down the Holmenkoll Line, finally tipping over at Midtstuen.

One person was killed and four were seriously injured, leading to a safety inspection of the old teak cars used on the line; the HkB 600 units were withdrawn from service, but were reintroduced after some refits.

However, the Sognsvann and Røa Line was upgraded to metro standard between 1992 and 1995, and could start using T1000 stock with only third-rail support.

The high development cost was subsidised by the Norwegian government, who saw the project as potentially establishing a new industrial export product.

Four traction motors, each of 143 kW (192 hp), powered the car, giving a top speed of 100 km/h (62 mph) and an acceleration of 1.3 m/s2 (4.3 ft/s2).

[5][6] The Norwegian State Railways had been considering a modified version for use on the Flåm and Voss Lines, but those plans were also soon abandoned.

Although its design was found to be unsuitable, the T2000 was initially not planned to be replaced by the MX3000, as the line was to remain with overhead wires and none of the new MX3000 trains are equipped with pantographs.

[7] However, following Oslo's decision to host the FIS Nordic World Ski Championships 2011, it was decided to upgrade the Holmenkollen Line to full metro standard, allowing longer than two-car trains.

[8] A proposal to downgrade the line to light rail standard and make it part of the Oslo Tramway was rejected.

[10] Kollektivtransportproduksjon, the successor of Oslo Sporveier, stated that procuring spare parts was becoming nearly impossible and that the small size of the series forced high maintenance costs.

Alternatively, the city council has been recommended by Kollektivtransportproduksjon to purchase 15 new MX3000 three-car trains for NOK 250 million.

[14] Nevertheless, Ruter was in 2011 forced by the owner Oslo Vognselskap to keep renting the wagons for 22 million NOK each year, even though they were not in operation.