Published on 24 December 2025, the Rail Accident Investigation Branch set out how, at 11:25 on 6 September 2024, nine of a freight train’s 24 fully laden wagons derailed on a bridge over a public footpath in Audenshaw, Greater Manchester. No one was injured, but the line was closed for around eight weeks while repairs were completed.
Investigators concluded the derailment was triggered by loss of gauge restraint. The rails were carried on a longitudinal bearer system, with baseplates screwed to longitudinal timber bearers rather than supported on sleepers and ballast. Multiple baseplate screws on the right‑hand rail had failed by fatigue, allowing the gauge to widen and the wheels to drop inside the rail.
RAIB’s analysis found the screw configuration used on the bridge did not achieve an infinite fatigue life, even though train‑induced forces were below maximum limits set out in Network Rail standards. Traffic volumes over the bridge have risen since 2015, accelerating fatigue accumulation in the screws.
Network Rail’s inspection arrangements did not reliably detect failed or failing screws. Automated measurements and manual checks were not capable of identifying this failure mode, and dynamic track geometry remained within standards, so no further action was mandated. Earlier screw failures had not been treated as warnings of a wider problem.
Two organisational causes were highlighted. RAIB says Network Rail lacked effective end‑to‑end processes for managing LBS assets across design assurance, installation, inspection and maintenance. In addition, the local track team had neither recorded nor reported previous screw failures, and this gap was not corrected by assurance activity over several years.
Eight recommendations are addressed to Network Rail: strengthen component assurance for LBS designs; update guidance for design, installation, maintenance and failure reporting; improve staff competence for LBS oversight; enhance interfaces between track and structures teams; assess how supporting‑structure condition affects track behaviour; review traffic‑driven effects on LBS and adjust design or inspection; improve national LBS asset records; and tighten assurance of inspection and maintenance record‑keeping.
For practitioners, the central message is that compliance with force limits alone is not a proxy for fatigue resilience in fixings on longitudinal bearer systems. Maintenance and engineering teams will need to focus on fastener condition, treat repeated localised failures as system indicators, and ensure traffic changes are reflected in plans for inspection, renewal and design.
The report also underscores an interface risk at structures where LBS is used. Effective control depends on clear ownership between track and structures, robust records of configuration and work done, and the ability to evidence that inspections can detect fastener deterioration before gauge restraint is compromised.
Oversight now moves to the safety authority. The Office of Rail and Road handles RAIB recommendations, assesses the adequacy of responses from duty‑holders, and reports progress back to RAIB using agreed status definitions; further regulatory action can follow where responses are insufficient.
For operators and local authorities, the operational impact at Audenshaw-an eight‑week closure with no injuries-illustrates the value of targeted assurance at similar sites. RAIB has also released a short explainer video to support briefings for track and structures teams.