Rail Accident Investigation Branch
At about 11:32 hrs on Tuesday 28 January 2020, a freight train derailed while travelling over a set of points at Eastleigh West Junction, immediately south of Eastleigh station. The locomotive hauling the train ran derailed for about 35 metres, causing significant damage to the infrastructure. Four wagons subsequently derailed on the damaged track. Nobody was injured in the accident.
Some of the fastenings that hold the rails to the concrete bearers that support them had fractured, prior to the passage of the train. This allowed one of the rails to move outwards under the train, breaking further fastenings and causing the locomotives wheels to drop inside the rail, as it moved further outwards. The design of these fastenings made them more prone to this type of failure when subjected to high lateral forces, which were present at these points due to the track geometry at the site and the curving characteristics of the locomotive. The local track maintenance team had not identified any relevant faults prior to the derailment as the fastenings had fractured below the surface of the concrete bearer and these failures were not apparent during visual inspections. Despite previous faults of a similar nature elsewhere, Network Rail had not developed an effective inspection regime to detect such failures. Measurements of the track geometry of this set of points had also not detected any indication of deterioration in the track fastening system.
RAIB also observed that the maintenance delivery unit at Eastleigh was not effectively managing the maintenance of its track assets, and that evidence identified for preservation as part of this accident investigation was lost during the track repair work undertaken by Network Rail after the derailment.
RAIB has identified two recommendations and two learning points as a result of the investigation. The recommendations are both addressed to Network Rail. The first regards the development of a management strategy to address the ongoing risk of failure of track fastening systems of the type involved in the derailment. The second concerns a review of how Network Rail measures dynamic track gauge on lines that are not monitored by a track measurement train.
The first learning point concerns the importance of ensuring the correct cause of engineering failures is identified, and that subsequent actions are taken to control the associated risks. The second learning point reminds rail industry bodies of the importance of preserving evidence for safety investigations, and their legal duty to do so.