C1/2009R Safety failure in automatic train protection observed on 30 december 2008 on the Kerava-Lahti direction of line, Finland

According to a deviation notification a safety problem was encountered in Korvensuo on 30 December 2008. Engine drivers notified that they were receiving restrictive information. A distant signal was indicating stop even though a balise at the previous signal had given to the automatic train protection equipment (ATP) the preliminary information that driving at the fastest speed was permitted (proceed Fsl), and, as the train caught sight of the subsequent main signal, it showed the proceed aspect.

The reasons for the faulty ATP operation was that an outdated card version had been placed in the IM-module (signal box computer) controlling data transfer between Haarajoki and Korvensuo signal boxes. The wrong flash card had been installed because the software version had not been verified before installing the card. The installers said that this was because verification equipment was not operational due to the transfer of the office to another location. The card had also not been marked sufficiently clearly.

The situation was temporarily fixed once the deviation had become apparent by setting an 80 km/h speed limit in the area. The Thales "Emergency Team" met on 5 January 2009 to analyse the situation. Once the reason for the irregularity was observed, a new flash card was installed in the Haarajoki signal box module on 5 January 2009 at 23.00. The operations were tested and on 7 January 2009 the 80 km/h speed limit was lifted from the area.

In order to prevent the installation of wrong cards, the Accident Investigation Board recommends that signal box adjustment and repair work inspections, and documentation relating to them, should be supervised and the importance of inspections should be emphasised in signal box maintenance training. In addition, component up-to-datedness should be clearly marked on the component and personnel should be made aware of what the latest version in connection with maintenance actions is.

C1/2009R Report (pdf, 0.61 Mt)

•Recommendation S300

•Recommendation S301