A 133-year-old footbridge on a heritage railway in Gloucestershire was destroyed after a volunteer incorrectly loaded a digger onto an engineering train, a Rail Accident Investigation Branch (RAIB) report has found.

The Grade II-listed wrought-iron bridge at St Mary’s Halt in Lydney collapsed at around 10.55 BST on Thursday 14 August. Believed to be the last remaining structure from the historic Severn and Wye Railway, the bridge had only been restored in 2019.

The RAIB investigation concluded that the eight-tonne digger was loaded by a Dean Forest Railway volunteer who had not completed the necessary practical training and misjudged the height of the vehicle’s arm. The movement of the excavator required a qualified operator to load it at Lydney Junction and unload it at Whitecroft, three miles away.

On the day of the incident, the qualified volunteer was delayed, so another volunteer who had only passed the theory test agreed to load the digger. Although they had prior experience moving a smaller six-tonne excavator, they had not received the additional training required for the larger vehicle.

During previous transfers, the smaller digger’s bucket had rested on the raised deck of the wagon, keeping it below the maximum permitted height. For the eight-tonne digger, however, the bucket was 26cm (10.2 inches) higher than the underside of the footbridge, making collision unavoidable. RAIB noted that if the bucket had been stored on the lower deck, the bridge would have been cleared safely.

The report also highlighted several organisational shortcomings. Dean Forest Railway had no written instructions specifying how the excavator’s bucket should be stowed for transport, and the height of the new digger had not been checked against structures on the line since its acquisition in 2024. Furthermore, no process existed to verify the height of loads departing Lydney Junction, leaving over-height vehicles undetected.

Fortunately, no one was injured, although debris fell onto the station platform and the moving train.

Since the incident, Dean Forest Railway has commissioned structural engineers to assess the bridge and produce a detailed survey. While RAIB does not issue formal recommendations in this safety digest, the railway said it has reviewed and updated procedures to prevent a recurrence.

The railway expressed its gratitude to staff, volunteers, and industry partners for their professionalism during the incident, noting that lessons learned have already been implemented.

Image: RAIB