The Roslagsbanan line was Sweden’s first electric railway. It is almost 70 km long, and narrow gauge. When the line was threatened with closure, SL decided to renew the rolling stock, renovate the stations and lay new rails and sleepers in a huge project that also involved replacing the 30-year-old operational monitoring equipment.

In the early 1990s, Cactus was asked to supply a new traffic management system.

Constant improvements to the line, including new interlocking systems, have required Cactus to demonstrate great flexibility and adaptability.

All in one place.

All traffic monitoring is handled from a control room. This has a row of six screens that provide an overview of the whole line. Each station has its own direct link to the central system. Out at every station there is either a PLC and relay interlocking or a newer electronic interlocking system. Altogether these handle some 3,700 indications and 2,300 commands.

An out-of-the-ordinary system

The system is based on traditional centralised interlocking functions, which means remote control and feedback from every station. But the system can do a lot more:

  • Timetable control with reports. All arrivals and departures are logged and compared with the timetable. Delays (and early departures) are marked in the log and displayed in charts.

  • Automatic Route Setting. According to the timetables and the traffic situation, the system executes automatic route setting for optimum traffic management. Of course the operator can take over and perform these operations manually at any time.

  • Reconstruction in case of disruption. Everything that happens in the system is stored automatically. Then, if an incident occurs, the position can be studied in detail afterwards. Incident by incident can be played back and you can check the course of events in both the images and the log.