RAIB published Report 10/2025 on 24 December 2025 on the Audenshaw freight derailment. At about 11:25 on 6 September 2024, nine of 24 loaded wagons derailed on a bridge; no injuries; the line closed for around eight weeks.
Investigators found gauge spread after multiple baseplate screws failed on the bridge’s longitudinal bearer system, allowing right‑hand wheels to drop into the widening gap.
The bridge used longitudinal timber bearers installed in 2007. RAIB’s analysis indicated the screws did not have infinite fatigue life in this configuration; train forces were within Network Rail limits, but increased traffic since 2015 accelerated fatigue.
Records showed at least three earlier screw failures at the same locations, including one before 2020; required records were incomplete.
Automated and manual inspections did not reliably detect failing screws. Track geometry measurements remained within permitted limits, so no intervention was mandated, and earlier failures were not treated as significant by local teams.
Policy Wire analysis: The sequence described by RAIB points to a design‑assured but fatigue‑limited fixing arrangement on timber bearers. Compliance with train loading limits did not ensure indefinite service life, indicating a need to reassess assumptions on fastener durability, renewal intervals and the effect of traffic growth on LBS sites.
Policy Wire analysis: Inspection regimes that rely on geometry outputs are poorly suited to detecting isolated fastener fatigue on LBS bridges. The direction of travel is towards condition‑based checks, clearer ownership between track and structures, and a targeted census so that high‑risk configurations can be prioritised for remedial work and competence‑based interventions.
RAIB makes eight recommendations to Network Rail: strengthen component assurance for LBS designs; improve management guidance covering design, installation, maintenance and failure reporting; ensure staff competence; improve track‑structures interfaces; understand support‑structure effects on track behaviour; assess traffic‑change impacts; complete LBS asset records; and tighten assurance of record‑keeping.
Policy Wire analysis: If implemented, these measures would require updates to internal standards, work instructions and training for teams responsible for track on structures. Assurance will need to evidence accurate record‑keeping and effective escalation when component failures are discovered, with data quality treated as a safety control in its own right.