Every working day, half a million passengers make a million or more journeys on the underground from just over 100 stations. The underground runs frequently – in the city centre, there is a train every two to five minutes on weekdays.

Back in the 1930s there were plans to build an underground in Stockholm as a backbone for the city’s public transport. The plans were held up, but after the Second World War, things started in earnest. Today, the system has three lines, each with its own control centre.


It started with the alarm collection system

In 1991, Cactus received its first order from Storstockholms Lokaltrafik (SL) – a complete ready-to-run alarm collection system for all stations on the underground. Its operator stations were based on workstations with exceptional graphic capabilities for the time. Something that was much appreciated by SL’s technicians.

The delivery proved to be crucial to our future TMS systems. The ability of Cactus to manage the project with complete control over schedules, promised functions and agreed costs meant that Cactus was invited to take part in future procurement processes for TMS systems.


Redundant fibre network

The system originally included three servers, one for each control centre. Now it has been upgraded to a central dual computer solution with distributed workstations.

SL’s redundant fibre network is a major component of the overall system solution. The fibre network is completely insensitive to electrical interference, and is designed as a loop to go on working even when there is an electrical failure.


Common operations management

SL now has the monitoring of both the underground and other technical systems concentrated in one operations control centre, the DLC.

The alarm collection system from Cactus supports the DLC by collecting major alarms from all underground stations and all Cactus sub-systems.

The function of the system has changed over the years. Today it has gained in importance for passenger information with its tannoy control, and for increased passenger safety, monitoring attack and fire alarms from the stations.


Central statistics server.

Cactus has also contributed a central statistics server. This plays a major role with its comprehensive storage and reporting facilities for all the sub-systems. 

Opened: 1950

Vehicle type: C20, C6

Route length: 109 km

Track length: 276 km

Number of stations/stops: 101

Number of vehicles: 535

Number of points: 688

Number of signals: 726

Track gauge: 1,435 mm

Max speed: 90 km/h