The recommendations are published in the BEA-TT's preliminary report into the derailment of a Paris - Limoges Intercity train at Brétigny-sur-Orge south of Paris on July 12 2013 in which seven people were killed and 32 injured.
The rear four coaches of the train were derailed by a dislodged fishplate (pictured below) in a double-slip crossing 150m to the north of the station. The fishplate had become detached and as the train passed over the crossing the fishplate pivoted around the one headless bolt remaining in place and blocked the flangeway.
The fishplate is likely to have become dislodged due to cracking in the web of the extremity of the switch frog which had developed during the months prior to the accident and which led to the failure of one bolt. After the head of this bolt had sheared off it put increased stress on the remaining three bolts causing the heads of another two bolts to shear off and the remaining bolt to work loose. BEA-TT points to the limitations of visual track inspections on an operational railway for the failure of an inspection on July 4 to detect the defect. Investigations are still continuing into the cause of the accident.
While BEA-TT will continue its investigation into the accident, it has already made three recommendations to SNCF:
- to improve its understanding of bolted track devices by strengthening the technical specifications and the quality of the components used, and ensuring that it complies with the requirements for tightening bolts, as well as the specifications and rules for installing and maintaining such assemblies
- to clarify and strengthen the rules on the detection of abnormalities in bolted turnouts, and specify the maximum time between work being out and its inspection, and
- to identify turnouts or groups of turnouts with features that require more-frequent and enhanced maintenance.
At Cuvillier's request, SNCF and RFF launched a four-year €410m programme in October 2013 to accelerate the renewal of turnouts, to develop innovative methods for monitoring turnouts such as video monitoring and analysis of rail, and a thorough revision of staff training.