C3/2004R Freight train car derailing at Joensuu on 8 May, 2004
On Saturday May 8, 2004 a rail indicent took place at Joensuu where one car of a freight train travelling from Ilomantsi to Joensuu derailed and tilted so as to drop a part of its roundwood load to the railway bed. The incident occurred when the freight train travelling from Ilomantsi to Joensuu arrived in the south end of Joensuu yard at a turnout where the Ilomantsi line enters Joensuu Railway yard. At the turnout, the fourth last car of the train derailed. The train continued running over a distance of about 150 meters and then stopped. No personal injury resulted from the incident. The derailed car broke track equipment and was itself damaged beyond repair. On the railway line, the incident caused a ten hour interruption in the rail services heading southward from Joensuu.
The incident was caused by a heat curve in the track four kilometers before Joensuu that had been generated as a result of a thermal expansion of the rails. Actually the train did not derail at the heat curve but some train buffers bumped ”crosswise” and caused the car to proceed somewhat transversely and hence forced the track to spead. The derailing took place in the south end of Joensuu railway yard when the train arrived at a more rigidly supported turnout with a heavier rail which resisted the stress of speading. When the train arrived at the turnout, the left wheel flange of the front wheelset of the fourth last car of the train raised above the rail and then the right wheel fell inside the track and the car derailed.
In the section of the track where the heat curve had generated, there was sleeper replacement work going on. In fact the track had been temporarily opened for traffic the previous day, with the intention of packing the track by using a tamping machine on Monday. At the date of the incident the outdoor temperature rose to +26°C.
To prevent corresponding incidents in the future, the Accident Investigation Board of Finland recommends that in all work site plans, condition limits be specified for unfinished track work sites that are temporarily opened for traffic. The condition limits would unambiguously define the circumstances where the condition of the track no longer permits its utilization as due to a risk of generation of a heat curve or as due to other changes in the track condition.