| Tay Bridge disaster | |
|---|---|
 A contemporary illustration | |
| Details | |
| Date | 28 December 1879 19:16 (7:16 PM) |
| Location | Tay Rail Bridge, Firth of Tay, Dundee |
| Country | Scotland |
| Line | Edinburgh to Aberdeen Line |
| Operator | North British Railway |
| Incident type | Bridge collapse |
| Cause | Structural failure |
| Statistics | |
| Trains | 1 |
| Deaths | 75 maximum estimate 59 known dead |
| List of UK rail accidents by year | |
The Tay Bridge disaster occurred during a violent European windstorm on Sunday 28 December 1879, when the first Tay Rail Bridge collapsed as a North British Railway (NBR) passenger train on the Edinburgh to Aberdeen Line from Burntisland bound for its final destination of Dundee passed over it, killing all aboard. The bridge—designed by Sir Thomas Bouch—used lattice girders supported by iron piers, with cast iron columns and wrought iron cross-bracing. The piers were narrower and their cross-bracing was less extensive and robust than on previous similar designs by Bouch.
Bouch had sought expert advice on wind loading when designing a proposed rail bridge over the Firth of Forth; as a result of that advice he had made no explicit allowance for wind loading in the design of the Tay Bridge. There were other flaws in detailed design, in maintenance, and in quality control of castings, all of which were, at least in part, Bouch's responsibility.
Bouch died less than a year after the disaster, his reputation ruined. Future British bridge designs had to allow for wind loadings of up to 56 pounds per square foot (2.7 kilopascals). Bouch's design for the Forth Bridge was not used.
As of 2024, it remains the fifth-deadliest railway accident in the history of the United Kingdom, as well as the second deadliest rail accident in Scottish history, being surpassed by the UK's deadliest: the Quintinshill rail disaster.