RAIBA freight train derailed due to undetected “failed” screws on the track, an investigation has found.
The train came off the tracks near Sidmouth Street, in Audenshaw, Greater Manchester, on 6 September 2024.
The incident was caused by the failure of multiple screws, which caused the track to widen, an investigation and report by the Rail Accident Investigation Branch (RAIB) concluded. The RAIB has made eight recommendations to prevent a similar incident in future.
Network Rail says it “fully accepts” the findings of the RAIB report and that repairs and safety work have been completed at the bridge.
What happened?
At about 11:25 BST on the day of the derailment, the freight train came off the tracks as it crossed a bridge carrying the railway over a public footpath in Audenshaw.
The derailment involved nine of the train’s 24 fully laden wagons and led to extensive damage to the track, the bridge and some of the wagons.
No one was injured during the accident, but the railway at this location was closed for about eight weeks while repairs took place.
RAIBThe railway tracks over the bridge were installed on a non-typical longitudinal bearer system (LBS), the report said.
The report concluded the derailment was caused by a “loss of track gauge restraint”, which caused the distance between the tracks to widen and allowed the wagons’ wheels to drop from the rails.
This was traced back to the failure of multiple screws, the report said.
The investigation found the screws had suffered fatigue damage before the derailment. Inspection and maintenance records confirmed at least three previous screw failures, including one before 2020, in the same location.
However, many records were unavailable and the lack of proper reporting and recording allowed these issues to go unaddressed, the RAIB found.
The investigation also found that those screws which had failed, or were failing before the passage of the train, had not been detected by Network Rail’s inspection regime.
This was because both the automated and manual inspection regimes were not capable of reliably detecting this type of failure.
The driver had two years’ experience of working as a train driver and no issues were identified with how the train was being driven at the time of the incident, the RAIB said.
Future prevention
The RAIB makes eight recommendations, including “managing the competence” of staff who manage the tracks and ensuring better records of inspections and reporting of component failures.
“There were two underlying factors. Network Rail did not have effective processes for managing LBS assets, in regard to their design assurance, installation, inspection and maintenance,” the RAIB said.
“The track team in the maintenance unit responsible for the LBS at this bridge had neither recorded, nor reported, previous screw failures, and this had not been identified nor corrected by Network Rail’s assurance regime over a period of years.”
Network Rail said it fully accepted the findings of the RAIB report.
“Repairs and safety work at this bridge have been completed and Network Rail has also introduced enhanced inspection and maintenance regimes at similar locations across the region to remove any potential safety risks,” a spokesperson said.
