The Dee Bridge disaster was a rail accident that occurred on 24 May 1847 in Chester, England, that resulted in five fatalities.
It was finished in September 1846, and opened for local traffic after approval by the first Railway Inspector, General Charles Pasley.
The lead investigator was Captain Simmons of the Royal Engineers, and his report suggested that repeated flexing of the girder weakened it substantially.
Stephenson maintained that the locomotive derailed whilst crossing the bridge, and the impact force against the girder caused it to fracture.
The Norwood accident in 1891 led to a review of all similar structures by Sir John Fowler, who recommended their replacement.