C5/1999R Freight wagon derailing at Kiuruvesi, on March 16, 1999
On Tuesday, 16 March 1999, a train accident occurred, where one wagon of a freight train running from Iisalmia via Ylivieska towards Kokkola derailed. In the accident the derailed wagon and about 5km of track were damaged.
When the train was at a distance of about 8 km from Kiuruvesi station, the right-side bearings of the rear axle of the 13 th wagon stuck, and as a result the axle broke. Then the rear end of the wagon dropped and the front wheelset raised above the rails and derailed. The front wheelset continued travelling on the left side of the rails. Having travelled thus beside the rails about 5km, the right wheel of the wheelset hit the centre drum of a level crossing, which made the front part of the wagon turn further to the left. Then the brake conduit of the train broke and the train brakes switched on. The rear wheelset of the derailed wagon remained on the rails while the front wheelset travelled at about half a meter off the track.
The accident was caused by the damaged wheelset having stuck and locked earlier, apparently in connection with the starting off of the train. As a result wheelflats were generated by braking, and while the train was running an excessive vertical impact-type load stressed the bearings. A bearing heated and damaged and finally it stuck. Partially the wear of the bearing or its insufficient lubrication may have contributed to the bearing damage, e.g. as due to water having penetrated into the axle-box.
When the wagon passed two hot-box detectors, the bearing was already damaged and the temperature of the axle-box was clearly higher than that of the other axle-boxes. As there was no alarm signal emitted, the Accident Investigation Board of Finland recommends a revised definition of the alarm motives and the corresponding limit values for the hot-box detectors. The Accident Investigation Board of Finland furthermore recommends alternative control methods to be adopted in situations where the hot-box detector - for one reason or another - is out-of operation. The Board also reiterates its earlier recommendations for the development of wheelflat and hot-box detectors.