RAIB issues safety advice after freight train derailment

The Rail Accident Investigation Branch (RAIB) has issued an urgent safety advice notice regarding bridges with longitudinal timber systems after initial analysis from RAIB identified that it could be the cause of a derailment in Greater Manchester in September.

On September 6, a freight train travelling between Peak Forest and Salford derailed as it passed over a bridge in Audenshaw.

The Class 66 locomotive and nine wagons derailed with the last three of the wagons coming to a stand on the bridge itself.

RAIB’s initial investigation has identified that the gauge spread in the first half of the bridge caused the incident. The rails on the bridge were supported by PAN M6 Baseplates but were held onto the timber by just two LSA chair screws. On site, investigators recovered 13 failed LSA chair screws from the baseplates of the low-side rail. None of these screws were marked with ‘HT’ on their heads, indicating that the chair screws were probably not made of high-tensile strength material.

The advice is that existing inspections and maintenance regimes may not be enough to find failures of baseplate chair screws, which can lead to a loss in track support in longitudinal timber systems with hardwood timber and more rigorous inspection may be needed.

RAIB had already identified a similar issue which was also hard to detect in a freight train derailment at Sheffield station in 2020.