C9/2002R Signal malfunctioning on Kouvola-Harju section of line on 29 June, 2002

On 29 June, 2002 the signalling equipment displayed a malfunctioning on the Kouvola - Harju section of line in Finland. The remote control operator had set the route for a train travelling from Harju toward Kouvola; nevertheless the first line block signal on the opposite running direction, i.e. from Kouvola, simultaneously displayed a "proceed" aspect.

The malfunctioning of the signal was due to a deficient signalling equipment program that mani-fested its shortcomings in a two-way exploitation of the connection. According to laboratory tests conducted by the equipment supplier, the signal control module displayed a malfunctioning if the data transmission connections rapidly switch over from the main connection to the back-up con-nection and back again.

The equipment supplier has remedied the shortcoming and the Finnish Rail Administration has approved the repair measures and the operating reliability of the equipment in terms of safety risks. Moreover the Accident Investigation Board of Finland recommends that the liability for the maintenance of signalling equipment be entirely bestowed on one single party.

C9/2002R Report (pdf, 0.46 Mt)

•Recommendation S205