Stockholm Metro

Escalators at Rådhuset station on the blue line

There are 100 stations in use in the Stockholm metro (of which 47 are underground). One station, Kymlinge, was built but never put into use. One station has been taken out of use and demolished. The old surface station at Bagarmossen was demolished and replaced with a new underground station, this being prior to the metro extension to the Skarpnäck metro station.

The Stockholm metro is well known for the decoration of its stations; it has been called the longest art gallery in the world.[9] Several of the stations (especially on the Blue Line) are left with the bedrock exposed, crude and unfinished, or as part of the decorations. At Rissne, an informative fresco about the history of Earth's civilizations runs along both sides of the platform.

Tunnels near Östermalmstorg station

Near-geographically accurate map of the Stockholm metro

The following details relate to the present network. The designations "Blue line", etc., have only been used since the late 1970s, and officially only since the 1990s. They originated from the fact that the "blue line" tended to operate newer train stock painted blue, while the "Green line" had older stock in the original green livery. There was never any red painted stock, though, but red (or originally orange) was chosen to differentiate this line from the other two networks on route maps.

• The Green line (officially Tunnelbana 1, or "Metro 1") has three routes and 49 stations: 12 underground (nine concrete, three rock) and 37 above ground stations. It is 41.256 kilometres (25.635 mi) long. It was opened on 1 October 1950 (between Slussen and Hökarängen stations) and is used by 451,000 passengers per workday or 146 million per year (2005).

Main article: Green line (Stockholm metro)

• The Red line (Tunnelbana 2) has two routes and 36 stations: 20 underground (four concrete, 16 rock) and 15 above ground stations. It is 41.238 kilometres (25.624 mi) long (only 18 metres (59 ft) shorter than the Green line), and was opened on 5 April 1964. It is used by 394,000 passengers per workday or 128 million per year (2005).

Main article: Red line (Stockholm metro)

• The Blue line (Tunnelbana 3) has two routes and 20 stations: 19 underground (all rock) and one elevated station. It is 25.516 kilometres (15.855 mi) long. It was opened on 31 August 1975 and is used by 171,000 passengers per workday or 55 million per year (2005).
  Trains operate from 05:00 to 01:00, with extended all night service on Fridays and Saturdays. All lines have trains every 10 minutes during the day, reduced to every 15 minutes in early mornings and late evenings, and every 30 minutes at night. Additional trains during peak hours gives a train every 5–6 minutes on most stations, with 2–3 minutes between trains on the central parts of the network.

Main article: Blue line (Stockholm metro)

The metro contains four interchanges (T-Centralen, Slussen, Gamla Stan and Fridhemsplan) and lacks any kind of circular or partly circular line (although Stockholm has a semi-circular light rail line, Tvärbanan). A wide majority of the metro stations are located in suburbs, but the network is centred on T-Centralen where all trains in the entire network pass.

In the past, there have been additional route numbers in use for trains operated on part of a line, or during peak hours only. For example, route 23 was used for a peak relief train for route 13, which in the 1970s was operated between Sätra and Östermalmstorg and during the 1990s between Norsborg and Mörby Centrum.

There is a connection to the main rail network, which is used for deliveries of new trains and some other purposes. In this case trains are pulled by locomotives since the electrical and other standards are different.[11] This connection consists of a track to Tvärbanan at the Globen station and a rail track from the Liljeholmen Tvärbanan station to the Älvsjö railway station.

There are three main types of cars in the Stockholm metro: the newer C20 and C30 stocks, and the older C1–C15 stocks, which are collectively referred to as the Cx stock. A train typically consists of two or three cars of the C20 stock connected in double or triple configuration (six or nine cars), two trainsets of the C30 stock connected in double configuration (8 cars), or six or eight cars of the Cx stock. A full length train—three C20 trainsets, two C30 trainsets, or eight Cx cars—is about 140 metres (460 ft) in length, and takes about 1,250 passengers, of which about 290 to 380 can be seated.[12][13][14][15][16][17] The Blue Line—as well as the Red Line (from Stadion to Mörby Centrum)—was built with longer platforms to allow running trains consisting of ten Cx cars. When the C20 was introduced, it appeared that trains consisting of four C20 cars would not fit completely on these platforms. However ten car Cx trains have only been used in service on the blue line, where except for the platforms at Husby, all platforms are built to fit ten car trains. As most of the red line platforms can only accommodate eight car trains, the ten car trains would only be able to run a distance of 6 stations between Stadion and Mörby Centrum, and therefore ten car trains have not been used in service on the red line.

There are 271 trainsets of the C20 stock, approximately 250 Cx stock trainsets and 96 C30 stock trainsets. The green line only uses C20 stock, and the C20 are used most of the time on the Blue Line and with the C30 stock on the Red Line. However, during rush hours, especially on shortened services, older cars are occasionally seen. Of the older cars the stocks, only C14 are still in use, operating on the blue line. C14 trains may occasionally show up on the red line as well. All trains are based at Hammarby, Högdalen and Vällingby depots on line 17, 18 and 19, Norsborg depot and Nyboda depot on line 13 and 14, and Rissne depot on line 10 and 11.

Historically the metro is converted from a tramway and the older sections were run as tramway for a few years. The naming convention for rolling stock comes from this, where A are motorised trams, B are unmotorised trams (trailers) and C are metro cars.

Interior of a C6H type car

The name Cx collectively refers to all the older types C1–C15. The only cars of the Cx stock still in use are C14. They are 17.32 m (56 ft 10 in) to 17.62 m (57 ft 10 in) in length, 2.8 m (9 ft 2 in) in width, 3.70 m (12 ft 2 in) to 3.78 m (12 ft 5 in) in height, and weigh 29 metric tons. The cars take 48 seated passengers, and 108 to 110 standing passengers. The C14 trains were built in the 1980s.[14]

Interior of a C20 car

The C20 car is double-articulated, 46.5 metres (152 ft 7 in) in length, 2.9 metres (9 ft 6 in) in width, 3.8 metres (12 ft 6 in) in height, and weighs 67 tonnes (66 long tons; 74 short tons). It uses only four bogies, two under the middle part, and one under each end part of car. The car takes 126 seated passengers, and 288 standing passengers. Three such units normally form a train. The C20 stock cars were built between 1997 and 2004 and first entered service in 1998.[16]

A single prototype car designated C20F stock is in use. Built on Bombardier Transportation's FICAS technology,[18] it has a lighter body, much thinner side walls, and more space compared to the regular C20, by using a sandwich-like composite construction of the body. It also has air-conditioning for passenger area, whereas standard C20 has air-conditioning only for the driver's cab. However only the last 70 C20 units produced (2200-2270) are equipped with air conditioning in the drivers cab. All other C20 units completely lack air conditioning. Therefore units lacking air conditioning are usually placed in the middle of trains and moved to the blue line during the summer, where the air conditioning is the least needed. The C20F weighs 65 tonnes (64 long tons; 72 short tons), other exterior measurements are the same as for the C20. The C20F has the same number of seats as the C20, but has space for 323 standing passengers.[17]

After about 20 years in service (22 years for the oldest cars and 16 years for the youngest cars), the C20 had reached about half its lifetime, and a refurbishment was necessary. The first refurbished train set (three cars) was officially put into service on November 20, 2020, and the refurbishment of all cars is expected to be completed in 2023. These refurbished cars are called C25, and they have, among other things, an upgraded interior similar to the C30.

The C30 is a new articulated train type manufactured by Bombardier Transportation which is delivered since 2018 for use on the red line. The first C30 train entered service on the red line on 11 August 2020.[19] They are formed in semi-permanent four car units with open gangways between cars, and with two bogies under each car. Two such units form a train. Compared to previous stock, the cars have fewer seats arranged in mixed longitudinal/transverse layout for increased capacity, similar to the C1 and refurbished C20 trains.[20] The C30 is the first full Stockholm metro train type to feature air-conditioning in both the passenger compartments and driver's cabs and are expected to cost 5 billion kronor.[21]

A train on the way between Liljeholmen metro station and Nyboda depot

The Stockholm metro runs electrically using a third rail with a nominal operating voltage of 650 V DC on line 13, 14, 17, 18 and 19; and 750 V DC on lines 10 and 11. Traffic in the metro moves on left-hand side, similarly to mainline trains in Sweden. Cars and trams still drove on the left in Sweden when the metro system opened.

The maximum speed is 80 km/h (50 mph) on the Red and Blue Lines, 70 km/h (43 mph) on the Green Line (50 km/h (31 mph) at the platforms). Maximum acceleration and deceleration is 0.8 m/s². The reason for the lower speed limit on the Green Line is due to tighter curves than on the other lines, because the Green Line was built by cut and cover under streets in the inner city, while the other lines are bored at greater depth. Two safety systems exist on the metro: the older system manufactured by Union Switch & Signal in use on the Red and Blue Lines and a modern automatic train operation (ATO) system in use on the Green Line manufactured by Siemens Mobility.

To allow close-running trains with a high level of safety, the metro uses a continuous signal safety system that sends information continually to the train's safety system. The signal is picked up from the rail tracks through two antennas placed in front of the first wheel axle and compared with data about the train's speed. Automatic braking is triggered if the train exceeds the maximum permitted speed at any time. The driver is given information about the speed limit through a display in the driver's cabin; in C20 stock, and in Cx stock outfitted for operation with the new signal system installed on the Green Line, this is a speedometer with a red maximum speed indicator (needle), while the traditional display in the Cx stock is a set of three lights indicating one of three permitted speeds (high, medium, low). The system allows two trains to come close to each other but prevents collisions occurring at speeds greater than 15 kilometres per hour (9.3 mph). More modern systems also ensure that stop signals are not passed.

Another possibility is automatic train operation, which helps the driver by driving the train automatically. However, the driver still operates the door controls and allows the train to start. ATO is as of 2023 only available on the Green line, where a new signal system was installed in the late-1990s. This signal system, together with the C20 rolling stock, permits the use of ATO. The signalling system on the Red Line was supposed to be replaced with a Communications-based train control (CBTC) system manufactured by Ansaldo STS under a contract awarded by SL in 2010, however SL cancelled said contract in 2017, reportedly after repeated delays in project implementation.[22][23]