Storm disasters, alas, are nothing new. One of the most tragic and best remembered in these islands occurred 116 years ago yesterday, and has been immortalised - some might say with more sympathy than talent - by the Scottish poet, William McGonagall:
Beautiful Railway Bridge of the Silv'ry Tay!
Alas, I am very sorry to say
That ninety lives have been taken away
On the last Sabbath day of 1879,
Which will be remember'd for a very long time.
With the expansion of the railway network in the second half of the last century, bridge building had become an important branch of engineering. At first, these bridges were built of stone or brick, and the primary challenge was to ensure they could withstand the greatest floods a river might provide; any stresses induced in the structure by the wind were insignificant compared to those which resulted from supporting its own great weight of masonry.
But towards the end of the century bridges began to be constructed from new materials - from iron at first and, later, steel. These new bridges were much lighter than their predecessors, and the stresses from wind pressure became a hazard of much greater significance - and to a large extent, an unknown quantity.
It was against this background, and at the height of a fierce storm, that the evening train from Edinburgh to Dundee set off to cross the River Tay on December 28th, 1879. The bridge had been completed 18 months before, and carried a single track over 74 spans; it described a gentle curve 80 feet above the river for the two miles of its length, and was considered a triumph of Victorian engineering and a monument to the Age of Progress.
It remains a moot point as to whether the bridge was unable to withstand the winds gusting to over 100 m.p.h., and therefore collapsed, carrying the train with it, or whether the motion of the train itself was the reason why the structure failed. In any event, the bridge collapsed, and the train plunged into the freezing river below, drowning all the passengers and crew on board.
After the event there were claims and counter-allegations about the design of the Tay Bridge, and it seemed obvious to many that the potential wind-loading had been grossly underestimated.
The tragedy raised questions, as indeed such an event would do today, about the relative merits of the various instruments for measuring windstrength, and the formulae used to convert their readings into the stresses likely to be experienced by a large structure.