Upgrading of technological safety systems

It was down to the traffic controller’s misjudgement that the train was authorised to be reversed onto a section of track that was not long enough for it. The situation escalated quickly and ended up requiring action from three traffic controllers. Reversing is a relatively common manoeuvre but still something that an individual traffic controller and an individual train driver rarely have to do.
The reversing train in this case had been given movement authority based on zero overlap from signalling control. This meant that there was no positive confirmation that the track would be clear after the signal marking the end of the movement authority. The on-board unit of the automatic train control system had been switched to shunting mode for the reversing manoeuvre. The on-board unit is located inside the cab at the front of the train, and the system was consequently not able to detect the carriages’ passing of the stop signal.
There was no technological system in play that could have prevented the accident after the human error was made.

The Finnish Transport Infrastructure Agency and Fintraffic Railway Ltd join forces to improve the safety of reversing and other degraded operations by putting into place an array of technological systems to safeguard against an accident in the event of human error.

Examples of ways to improve safety include prohibiting the giving of movement authority for reversing based on zero overlap at stations and stopping traffic behind a reversing train over a safe distance. The possibility of using the ETCS automatic train control system as a safety mechanism for reversing manoeuvres should also be explored. The identification and prevention of the risk of human error should be given more attention in operator training and in organisations’ safety management systems.

According to the Finnish Transport Infrastructure Agency (FTIA), it is difficult to build new technical safety systems/functionalities in existing safety devices, taking into account that they must meet the safety integrity level (SIL) requirements. They would also require changes to trackside equipment, such as track circuits and axle counters. With regard to reversing, the entity related to reversing has been specified in the Rail Transport and Shunting Safety Guidelines, and Fintraffic Railway Ltd has developed its work instructions related to reversing. As far as the future ETCS train control system is concerned, reversing has been taken into account in the specifications. Reversing takes place in the RV mode (Reversing functional mode), and the length of the reversing area is defined by a data packet sent by the radio block center (RBC), indicating the length in metres, direction and scale of the reversing area. The second data packet complements this by specifying the maximum permissible speed and control status. With these means, ETCS monitors the distance of the train to the border and initiates emergency braking if it passes the border.
In connection with the recommendation, Fintraffic Railway Ltd has carried out a review and prepared a report on how to use the 0 overlap. The form to use in reversing situations has also been updated, and the operating practices have been specified. With regard to the upcoming ETCS train control system, requirements related to reversing have been comprehensively included in the relevant requirements in cooperation with Fintraffic Railway and the Finnish Transport Infrastructure Agency. Fintraffic Railway’s new traffic control and management system ATLAS will also include features that are linked to these ETCS requirements.