Metro cars M1-M6 were mainly meant to test Strömberg electrical equipment and Valmet metro cars on the test track, 2,8 km, between the depot in Roihupelto and Herttoniemi. That double track line is nowadays a part of the present network. The trial train of six cars had thyristor chopper control. The car body was an arc-welded construction of light-alloy sections and sheets. The train was designed for full automatic service, but of course also with driver’s cabin. Every two-car set had different indoor look to test different interiors. Two two-car units had cushioned seats (2+3), orange or blue colours, and one unit had hard seats (2+3) of reinforced plastics. The lamps were also situated in different ways to find the best solutions.
All trial cars have been scrapped and recycled, only M3´s cab remains as a historical monument at the depot. When the scheduled traffic started, the trial train was found obsolete because of its old technique. That’s why it was moved to an isolated stump of rails, and so it was ensured that it never came to the main network again.
When the final series of cars (100´s) started to come, the traction motors were chosen to be three-phase AC induction motors. Automatic service was not chosen yet, and therefore the driver has a closed cabin. However, these 100-series cars were also intended for automatic operation, but ”reliability and safety have been given special consideration” as it was told in a brochure from 1981. Car bodies were built by welding together light-allow extrusions. Only small amounts of light-alloy sheets were used. Seating arrangement is 2+2 and the seats are made of reinforced plastics.
In future, the metro will have automatic operation, plans have started (2004).
Oulunkylä-Herttoniemi freight railway, 8.3 km, was originally built to serve the Herttoniemi oil and fuel port. It was constructed by the Port of Helsinki, so it was legally a private railway – a non-state railway. Traffic started in 1939 and its last days came in 1992. The track section from Herttoniemi to the metro depot line junction was lifted in 1993. The Oulunkylä-Herttoniemi line was always operated by VR with her locomotives and wagons. Nowadays the former harbour is a new housing area. The Vuosaari port is now under construction. After the port in Vuosaari has been opened, the Länsisatama port in Jätkäsaari will be closed. A new rail connection with VR can be constructed from Vuosaari metro station to the new harbour track yard. At that point, the old and long line, 5 km, from Oulunkylä to the metro depot will be dismantled. This railway is now owned by HKL.
The 100-series cars came by rail from Tampere to the metro depot. A Dv12 diesel locomotive hauled each metro train. When the trial train arrived, there was no connecting track from the depot to the port railway so the cars were lifted by cranes from the railway to the above metro bridge.
The 200-series cars came on lorries (and ferries) from Germany. They were unloaded from the lorries at the place where the depot track joins the former port railway.