club meeting - President:s Challenge

Speaker: Malcolm Riddle, President’s Challenge - The Tay Bridge Disaster.

When Malcolm started to research the ‘challenge’ subject he found two choices….! One was a poem with the same title and one was the story of the Tay Bridge Disaster. He firstly looked at the poem and fairly speedily dismissed it - the poem, written by Scottish poet William McGonagall in 1880, is widely regarded as the worst poem in the English language. The following is one verse to demonstrate the point:

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.

The real disaster - only Mark seemed to have heard of it - happened at 7:15pm on 28^th December 1879 when the Tay Bridge collapsed into the waters of the Tay Firth below. The train had six carriages and was carrying 75 passengers and crew from Edinburgh to Dundee.

The talk was illustrated by photographs and diagrams. We first looked at why the Tay Bridge had been built. The bridge was the result of a battle between two railway companies, the Scottish North British and the Caledonian Railways, for the control of the major railway routes to north east Scotland; to be the first to build the bridge, a bridge which also received local business and resident support. The designer of the bridge, Thomas Bouch, employed by the Scottish North British Railway Company, was an experienced bridge and structural engineer.

The foundation stone for the bridge was laid on 22^nd July 1871. The design was criticised as it was for a single track which would likely reduce capacity and stability. The nearby Wormit Foundry produced the metalwork for the construction. Shortly after building began Bouch was forced to change his plans as the bedrock was found to be more shallow than expected and not suitable for brick piers. The brick piers were to be replaced by braced cast iron columns on a reduced number of wider spans. The new plans provided lattice girders supported by iron piers with cast iron columns and wrought iron cross-bracing. The construction was less robust than other bridges Bouch had built. 72 of the spans were supported on girders below track level; the 13 navigation spans had spanning girders above track level, meaning trains would run through a tunnel of span girders.

Some interesting facts included:

Ø  5 years to build

Ø  600 workers

Ø  20 lives lost during construction

Ø  2 miles long - at the time it was the longest bridge in the world, a marvel of it’s time

Ø  Cost £30,000 in 1878

The bridge was opened on 31^st May 1879 and within one year it had boosted the fortunes of the North British Railway Company, Dundee and surrounding towns. Passenger numbers doubled between Dundee and Fife and freight increased by 40%. On 20^th June 1879 Queen Victoria crossed the bridge in the Royal train on her way south from Balmoral. Thomas Bouch was presented to the queen some days later, following which he was knighted.

Why did the bridge collapse? Malcolm discussed the information he had gleaned on the subject…… On the day of collapse there was a force 10/11 gale blowing from the west. We reflected there were 72 spans below track level and the 13 navigational spans that were more widely spaced in the middle of the bridge for the passage of ships. The columns were connected by diagonal ties, the piers were supported by concrete foundations resting on the bed of the firth. On the day of the disaster the train entered the bridge and when it got to the fourth high girder there was a sudden extra strong gust of wind which caused a compression failure to the columns on the second level on the leeward side. At this point the sway of the train and the girders was no longer circular about the base but was uni-directional downwards resulting in the failure of the girders and the consequent fall of the train into the water. All 13 navigational spans in the centre collapsed but the shorter spans were more able to resist damage.

When morning dawned there was a scene of horror. The high girders had vanished into the briny…..leaving a yawning gap. Salvage began without success - all passengers and crew had been killed. The locomotive was recovered, dropped back in and recovered for a second time; it continued in service after it had been repaired (costing £50) for another 40 years, being known by its drivers as ‘The Diver’.

News of the tragedy spread rapidly and a £5 reward was offered for every body recovered. Some were washed ashore in Dundee and others drifted to Wick. The shore at Broughton Ferry became the landing ground for personal effects and luggage. Further fatalities, bringing the number to 90, were sustained by workers working below the damaged structure on 11^th February 1880 when another section of the bridge collapsed. There were 3 public enquiries with the first concluding the bridge was badly designed, built and maintained. The quality of the materials used was questioned and allowance for wind loading not taken into account by Bouch. Bouch was broken in spirit following the disaster and became a recluse, dying of stress in October 1880 not long after the enquiry……. success to disaster. A full report was given to parliament in 1880.

There was a desire to re-build the bridge by North British Railway and local supporters. Parliament rejected the bill due to the design involvement of Bouch. The design of a new bridge, to be built parallel to the old, was influenced by the old but the height reduced. The track was to run as before. On 20^th June 1887, the 50^th anniversary of Queen Victoria’s accession to the throne, the new Tay Bridge was opened. A memorial to those who lost their lives was erected.

We were left with the question: was the disaster more than just an accident? It was certainly a turning point in engineering with a cautionary tale of ambition meeting catastrophe; cutting margins can result in devastating consequences. The disaster remains the 5^th deadliest railway accident in UK history and the 2^nd deadliest rail accident in Scottish history.

John thanked Malcolm on behalf of the Club. We are grateful for the talk being of the disaster and not the poem! As usual Malcolm’s talk was detailed and very interesting. Thank you.