Bully-Grenay english summary
At 11:10 a.m. on 29 July 2010, the first 19 wagons of SNCF Freight train 88214 derailed on track 2 at the entrance to Bully-Grenay station (Pas-de-Calais). These wagons, loaded with coal, jack-knifed and toppled over onto the tracks, just after the passenger building, thus blocking the two main tracks.
They came to rest with no casualties but caused significant damage to the railway infrastructures for an approximate distance of 600 m.
The 19 wagons involved were damaged and at least two of them were beyond repair. On the other hand, this accident had no environmental impacts.
On the first wagon, there were signs of a braking incident : certain brake head wear plates were reddened by the heat and heavily worn ; the wheels were very hot and some of them had very large flats and hollowed out wheel treads.
The accident was caused by a malfunction of the brake distributor on the first wagon of the convoy, which caused the blockage of the first two axles, the hollowing out of the wheel tread by the friction on the rail and then the derailment at the first switch point rail at Bully-Grenay Station.
This malfunction was probably caused by the presence of solid particles inside the distributor, originating from excess sealing adhesive remaining after the last servicing of this component.
Due to the place at which the blockage occurred and the lack of apparent clues, the anomaly could not be detected in time by the railway employees or by the automatic detectors.
The analysis of the causes and circumstances of the accident led to the formulation of three recommendations in the following areas :
Quality of the work carried out by the distributor repair workshop
Qualifications of the wagon component repairers
Density and consistency of the surveillance and anomaly detection system for trains in operation.