Sir Thomas Bouch


    Tay Bridge
  • Portobello Pier

December 28th 1879 was a dark day in the history of Civil Engineering. It was on this day, with a gale blowing, that the express from Edinburgh started the crossing of the Tay Bridge. As it entered the high girders on the bridge the towers failed and the train with its 75 passengers and crew fell into the Tay. All were killed.

Initially it was thought that the gale had been primarily responsible for the accident but a subsequent investigation firmly laid the responsibility at the door of the design engineer, Sir Thomas Bouch (1822 – 1880). The inquiry, drawing heavily on Nayef Mohyud-Din’s account listed a catalogue of errors:

  • Inadequate/no testing of the braces
  • Bolt holes wrongly cast
  • Towers not tied together adequately

Lessons from the Past

It could be argued that the most damning comment of all related to the failure to properly investigate reports of severe rattling of the Tay Bridge Towers after it opened in 1878. If this is accurate, then imagine a possible similar scene over 120 years later with the opening of the London Millennium Bridge. Let’s set an entirely imaginary scene:

Pedestrians: “This bridge is a bit wobbly Guv”

Chris Wise(Design Engineer): “Not my problem mate – you should walk across it properly”

That of course was not the outcome but as engineers we must obviously be alert to potential issues with our designs and be prepared to respond promptly. Learning from our mistakes is one thing but ignoring problems is quite another.

As a result of the Tay Bridge Disaster, history has been somewhat unkind to Bouch, overshadowing his other achievements. Particularly noteworthy however was his design of the first Roll-on-Roll-off Rail Ferry in the world. The ferry enabled faster crossing of the Firth of Forth from Granton to Burntisland. The Ferry opened in 1850 but with the completion of the Forth Bridge in 1890 the Ferry was withdrawn.

Despite his other achievements, the Tay Bridge Disaster ruined Bouch, and he died soon after, supposedly of ‘shear distraught’.

More Information

Interactive Models

Simple Warren Truss

A warren truss consists of longitudinal members joined only by angled cross members. The equilateral shaped design ensures stability and ease of design due to the resulting lack of bending forces in the members. Use this Push Me Pull Me



The Original Tay Bridge