On Sunday 27 August 2006 an unmanned locomotive became uncoupled from the rear of a freight train as it approached Heald Green station, between Manchester Piccadilly and Manchester Airport. The locomotive then ran back northwards in the direction the train had come from for around 3 miles, and through a worksite at East Didsbury station. The locomotive then paused momentarily at Burnage station, before returning back southwards because of the gradient and through the worksite again. The train was brought to a stop by a combination of the gradient and workers wedging a wooden post in front of one of the locomotive’s wheels.
The track workers at East Didsbury station were not positioned on the same line as the runaway locomotive and so there were no injuries. Minor damage was caused to trackside installations.
The immediate causes of the incident were that the rearmost wagon drawhook broke while the train was on a gradient, and that the trailing locomotive had no air supply available in its air reservoirs to apply the brakes. The report identified five causal factors, eight contributory factors and two underlying causes for the incident.
RAIB has made eight recommendations aimed at:
the design of the type of locomotive involved, and how equipment therein is described and labelled
wagon maintenance procedures
driver training and assessment
reviewing how critical information is passed to drivers and their understanding of it is assessed
processes for identifying and mitigating hazards introduced by technical or operational change.