Monitoring the occupancy of the metro tracks

In metro traffic, an exception signal is often used to manage disruptions. Typically, the cause is a fault in the track circuit, i.e. a fault in the monitoring of track occupancy.
When an exception signal is used, some of the safety systems are bypassed and the safety level is reduced.

Metropolitan Area Transport Ltd develop safety devices for the metro network in terms of monitoring track occupancy so that the need for an exception signal is reduced.

Metropolitan Area Transport Ltd is currently carrying out a track circuit replacement project approved in autumn 2022. The aim is to replace track vacancy monitoring equipment on the current track with new technology on the metro network to the east of Ruoholahti and, among other things, to reduce the number of ‘chip errors’ leading to the use of the exception signal. The project is under way, and axle counters will be introduced in 2026–2027. The need to use an exception signal in case of error can also be reduced by improving the response times in fault repair. A continuous practice adopted in relation to this is the regular monitoring of the response times to repairing faults in track circuits and other safety equipment and, if necessary, initiating measures to improve them.