It happened when a heavily loaded freight train ran out of control on the 1 in 100 Hencote incline, and was derailed on a set of trap points, eventually demolishing a signal box.
At approximately 05:50, the 03:56 Saltney to Pontypool Road freight train, formed of Class 47 diesel locomotive D1734 with 46 wagons, weighing a total of 775 tons, was approaching Coton Hill.
The driver did not have any recollection of the accident, and it was thought logical that he had assumed that the points were set for the main line and not the goods loop.
When the locomotive was being broken up some months later, it was found that its Automatic Warning System (AWS) equipment had been isolated, despite appearing to be in working order.
The driver would therefore have had no warning that the points were set for the goods loop ahead, though given the failure to stop, this would probably not have prevented the accident.