Report 10/2025: Derailment of a freight train at Audenshaw
Derailment of a freight train at Audenshaw, Greater Manchester, 6 September 2024.
Summary
At about 11:25 on 6 September 2024, a freight train derailed as it crossed a bridge that carries the railway over a public footpath in Audenshaw, Greater Manchester. The derailment involved 9 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 around 8 weeks, while repairs were undertaken.
The derailment occurred due to a loss of restraint of the track gauge between the rails. This caused the wagons’ wheels on the right-hand side to drop from the rail into this widening space.
The railway tracks over the bridge were installed on a longitudinal bearer system (LBS). An LBS is a track support arrangement in which the rails are mounted on timber bearers that run longitudinally under the rails and not on sleepers and ballast, as is typically found on the railway. The rails are mounted using baseplates, which are screwed onto the bearers.
The spread of the track’s gauge was caused by the failure of a number of the screws securing the baseplates to the longitudinal wooden bearers. Subsequent metallurgical examinations showed that these screws had sustained fatigue damage before the arrival of the train. RAIB examinations of a section of the LBS recovered from site found that there had been previous screw failures at the same locations. Records of inspection and maintenance activities confirmed that there had been at least three previous failures, with one occasion known to have been before 2020, although many of the required records were not available.
Vehicle dynamics analysis and fatigue calculations carried out by RAIB during this investigation showed that these screws were not expected to have an infinite fatigue life when installed in the configuration used on the bridge, even though the forces from trains on the track were below the maximum limits stated in Network Rail standards. The LBS was installed in 2007 and an increase in the volume of traffic over the bridge since 2015 had accelerated the rate of fatigue of the screws.
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. RAIB also found that the regular dynamic track geometry measurements were within the allowable limits in standards, so no further action was mandated. It further found that the significance of previous screw failures had not been appreciated by those responsible for inspecting and maintaining the LBS at this bridge.
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.
RAIB also found that 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.
Recommendations
RAIB has made eight recommendations to Network Rail. The first recommendation aims to give greater assurance of the components used in its designs of LBS. The second recommendation is to improve its management of LBSs, including design, installation and maintenance guidance, and the reporting of component failures. The third recommendation deals with the competence of staff who manage those assets.
The fourth recommendation is for Network Rail to improve the interfaces between the two disciplines responsible for the track and structures assets to better manage them. The fifth recommendation is for Network Rail to better understand the effects from the condition of the LBS supporting structure on the track’s behaviour.
The sixth recommendation is for Network Rail to review the way in which it assesses the effects of changes in rail traffic on its LBS assets and to consider any subsequent necessary changes in design, inspection or maintenance activity.
The seventh recommendation is to improve its records of its LBS assets, ensuring that it knows the configurations of its LBS assets nationwide.
The eighth recommendation is for Network Rail to improve its own assurance processes for LBS assets to ensure that staff are keeping accurate records of inspection and maintenance activities.
Video summary describing the accident at Audenshaw - link opens in new tab