Dee Bridge Disaster

The Dee bridge disaster was a rail accident that occurred on 24 May 1847 in Chester with five fatalities.

A new bridge across the River Dee was needed for the Chester and Holyhead Railway, a project planned in the 1840s for the expanding British railway system. It was built using cast iron girders, each of which was made of three very large castings dovetailed together. Each girder was strengthened by wrought iron bars along the length. It was finished in September 1846, and opened for local traffic after approval by the first Railway Inspector, General Charles Pasley. On 24 May 1847, a local train to Ruabon fell through the bridge. The accident resulted in five deaths (three passengers, the train guard, and the locomotive fireman) and nine serious injuries.

The bridge had been designed by Robert Stephenson, and he was accused of negligence by a local inquest. Although strong in compression, cast iron was known to be brittle in tension or bending, yet on the day of the accident the bridge deck was covered with track ballast to prevent the oak beams supporting the track from catching fire. Stephenson took this precaution because of a recent fire on the Great Western Railway at Uxbridge, London, where Isambard Kingdom Brunel's bridge caught fire and collapsed.