C4/2002R Bearing damage in freight car and derailing at Muhos on 27 May, 2002

On Monday 27 May 2002, at Muhos station, an axle of a freight car loaded with timber derailed. The train continued travelling over still a 15,2 km distance, damaging thus the track, and stopped on Pikkarala siding to wait for a meeting train. On the track between Muhos station and Hangas level crossing, practically all right-hand side (in the travel direction) inner rail fastenings were broken. Several level crossings between Muhos and Pikkarala display clearly detectable defects, while only Hangas level crossing collapsed entirely. The deck of Hangas level crossing, located about two kilometres away from Pikkarala, was damaged by the broken freight-car axle. In fact the deck clung to the derailed car causing thus the derailment of the entire car and the trailing bogie of the car in front of it. The Hangas level-crossing deck that had clung to the understructure of the cars, served as a traction frame for the derailed cars, until Pikkarala. In spite of the derailment of the cars, the track section between Hangas and Pikkarala remained almost undamaged. The turnout at Pikkarala station broke. The total costs generated by the incident exceeded € 290 000.

The derailing was caused by the breaking of an axle as a result of a bearing damage. The bearing damage again was most probably caused by an unscrewing of the fastening bolt of the bearing flange. The unscrewing of the bolt was most probably caused by a missing screw locking or an inadequate locking of the screw.

The Accident Investigation Board of Finland does not give any relevant recommendations, as a countersecuring system of the locking of the bearing-fastening bolts has now been adopted at VR’s workshops, and moreover in December 2002, the Finnish Rail Administration audited the operation of the Wheelset Department.

C4/2002R Report (pdf, 0.37 Mt)