The first Tay Rail Bridge at Dundee was a cast iron bridge that collapsed on 28 December 1879. The collapse occurred when a train passed over it during an aggressive stormy weather. This tragedy caused 75 deaths. There were two main reasons that lead to its collapse.
One reason was the poor material quality control and maintenance of the cast iron columns and wrought iron strut and tie bracing system. The iron piers were also more slender than they should be.
Another reason was that the designer Bouch did not include adequate wind loading during the design of the bridge. Bouch did sought advice given by well-known engineers, in which wind pressures as high as 40 psf might occur locally but wind pressures of 10 psf can be allowed for the design. However, the storm that lead to the collapse of the Tay Rail Bridge was estimated to have a Beaufort force of around 10/11. The gale force led to the failure of the lateral stability of the cross bracing system and its connections.
After the collapse, the Tay Rail Bridge was replaced by steel construction.
The building of the Tay Rail Bridge led to Bouch being knighted. But after it collapsed, his reputation was forever ruined. Wind loading in design is ever so important. So sad!