The immediate cause of the accident was the flange of the leading right-hand wheel of the tender climbing over the right-hand rail.

The causal factors were that a spring had been replaced on the tender with one which was not of the correct type and the track had become distorted without the track maintenance staff being aware of the problem.

The RAIB have made five recommendations to the Severn Valley Railway concerning its safety management system, its engineering procedures, communication of safety related information to its staff and volunteers and its audit process.