TAY BRIDGE DISASTER
It was a miserable evening in Dundee on the 28th December 1879. The rain was pouring and the wind, estimated to be gusting up to 80mph was howling. The storm registered around 10 to 11 on the Beaufort scale. At a little after 7pm, the Edinburgh train entered the newly opened Tay Bridge……
Designed and built by Sir Thomas Bouch, it was opened officially the year before. Bouch was famous for his design of the world’s first roll-on/roll off train ferry, which had been in operation across the Firth of Forth for almost thirty years. He was also responsible for the construction of several rail lines, Portobello Pier, a number of high profile bridges and viaducts and Waverley Station in Edinburgh. When Bouch received the commission for the Tay Bridge project, he also received a similar commission for a rail bridge across the Forth.
The Tay bridge was begun in 1871, and involved primarily laying foundations on a natural bedrock just below the surface of the estuary. Trial bores had apparently located the rock, but when the foundations came to be laid, it was discovered they lay deeper than originally anticipated, leading to Bouch redesigning the bridge with less piers and longer girders on the spans. Instead of the structure being fastened directly to the bedrock, now brick lined, wrought iron caissons (casings) were sunk, onto the surface of the rock, into which concrete was poured. The majority of the track at both the Dundee Station side and the Wormit side lay on the bridge surface, known as deck trusses, with inner wheel guards, whilst the central section had a higher set enclosed rail, ‘through trusses’, to give extra clearance underneath for passing ships. From the South (Wormit) side to the far centre of the bridge the rail was virtually level, however on the Northern side, to Dundee, there was a gradient slope of around 1 in 73, wrapping around a curved bend on the approach to the station.
Prior to the completion of the bridge, Bouch’s brother had died, leaving him a majority share of £35,000 in the foundry company he was a director of, Hopkins Gilkes and Co, Teeside, with a further £100,000 on guaranteed borrowings. Bouch was unable to get out of the arrangements, and therefore decided to use Gilkes to build the bridge. Certain components however were cast in a local Wormit foundry. Gilkes were in financial difficulties and the delays caused by certain aspects of re-design and so on with the bridge, led to further financial problems. This was later found reflected in the quality of a large majority of the structural metalwork.
In 1877, work was finally completed on the bridge, and after several tests with load, was opened officially for passenger trains on 1st June 1878 following a three-day Board inspection in the February, after which the inspector passed the bridge but noted that he would like to re-visit to observe the effects of adverse weather, notably high winds, on the bridge whilst trains journeyed over it. A speed limit of 25mph was attached to the bridge, which was single lane, working on a ‘baton’ token system to prevent trains attempting to cross in opposite directions simultaneously. In June 1879, Queen Victoria took the opportunity to travel the line, and crossed the bridge. Bouch was knighted shortly afterwards.
All looked good for the bridge, and for Bouch. His bridge was deemed a success, and he turned his attention to the project over the Firth of Forth. Foundations were already being laid. The work done by Gilkes was the last major project the company worked on, the following year they would close due to insolvency, but that was in the future. For now, though, there was a storm……
At around 7.13, the train slowed to collect the baton from the south side signalman. He turned and logged the entry in his book, and then paused to stoke his fire. At 7.16pm, the Dundee train entered the central section of the Bridge. With his friend in the signalers cabin, the two men’s witness accounts vary slightly, but the basic details remain the same. The friend saw the train give off some sparks from the east side when it reached a point about 200 metres across the bridge continuing until it was enclosed in the high girders, the lamps trackside lighting the way in the dark, then suddenly a bright flash of light followed by darkness. Nothing. The sparks, tail-lights, and flash vanished in one complete action. The man alerted the signalman, who looked up in disbelief. The train never appeared the other side. They watched, waited, but nothing. It had vanished. The signalman attempted to notify the cabin at the Dundee side, but the lines were down. Meanwhile a number of witnesses at the Northern side of the bridge, some with a full head on view, others with partially obscured varying views reported similar; the train entering the high girders, the sparks, the sudden darkness. One man reported briefly seeing two columns of spray briefly lit up by the oncoming train headlight before darkness. The conclusion was the same, the train was gone, taking up to 75 passengers and crew with it.
An enquiry into the disaster was convened, and wreckage from both the bridge and the train were used as evidence. Due to the variation of the marks on the carriages, it was decided that the train had not derailed and therefore no impact caused the collapse of the bridge. It was revealed that many of the castings of the metal were found to have up to half inch variants in thickness, some of which had been welded with extra “burning on” and filler. Inspections had been made shortly after the bridge had opened which revealed cracks in some of the columns and “chattering” in several of the ties. Extra diagonal bracing was added to compensate for the chattering and the cracked columns were wired bound for extra strength. Errors in the setting of the cement to stone base fixings including too smooth a finish on the stone and no wetting prior to adding the cement had let to poor adhesion of the fixing bolts, which consequently burst through the masonry. The connecting flanges were not fully faced to the next bracing, spigots were missing and bolts did not fit properly, being too short and narrow, causing them to glide free, with no hold-down power, giving up to two inches of free play to the columns near the top end.
Reports had been submitted from witnesses attesting to both lateral and vertical sway movement, up to 3 inches, and concerns over speed causing exceptional movement. Particularly on the South side, where the onus was on keeping ahead of the ferry below and the track sloped downhill it was noted that an expected crossing time of around 70 seconds was sometimes cut down to as little as 52 seconds. This was not replicated on journeys from the north end due to its uphill incline. Finally, the report noted that it was entirely possible that the resistance to wind force given to the bridge was quite possibly entirely underestimated at 15 pounds per foot. Extra margins had been introduced and discounted for the length of the bridge, the span distance, the design of piers versus girders and the strength of wind in Scotland across the estuary. It was proposed that forces up to 30 pounds per foot were not unreasonable. Weight factors of the train and speed were not included in all the calculations
Despite the three members of the court, Rothery, Yolland and Barlow failing to agree on all concerns of the report, nor reach a “Blame verdict” there was a lot of agreement of individual contributing factors. All these factors served to ensure the finger of blame was pointed squarely at the sub-standard design and construction of the bridge and in turn at the man responsible for its construction: Bouch. Rothery was happy to voice this blame, Yolland and Barlow declined to, allocation of blame was not required in a section 7 report being outside of the responsibilities of the reporters. Rothery claimed in his report that Yolland and Barlow were for the most part in agreement with his findings, they subsequently dismissed this acquiescence.
In 1883 a new two-track bridge began construction over the Tay, 18m away from and parallel with the original, whose pier bases can still be seen. Memorials to the disaster can be seen at either end, at Wormit and Dundee. Following the verdict of Failings in the Bouch designs, other examples of his work were consequently inspected. Work on the Forth Bridge was halted, with just the first pier in place. This can still be seen. The Portobello pier was demolished due to heavy rusting in 1917 just 46 years after it opened. An iron viaduct over the Esk was demolished after it was discovered its piers were noticeably out of alignment vertically, and his Redheugh bridge was demolished in 1896 after just 25 years of use when it was calculated that wind force over 19psf would have blown it over. Bouch lived long enough to see his reputation in tatters. Just 18 months after being knighted, and shortly after the findings of the enquiry, he died at his home in Moffat. He is buried in Edinburgh. He was spared the sight of all his “pioneering” construction being torn down due to their unsafe conditions.
Recovery efforts following the Tay bridge collapse found 46 bodies, enquiry estimates based on issue of season tickets, tickets sold and necessary staffing levels on board put the figure of souls aboard at approximately 75. An exact figure has never been specified. The locomotive had been discovered still sitting upright within the tracks it had fallen with, dispelling common misconception that the bridge had collapsed and the train had run OVER the edge of the gap remaining; the train had actually collapsed downwards with the track as the bridge gave way. The locomotive was subsequently raised, cleaned up and set back into service where it continued to run the line until 1919, with the nickname “the diver”. Many drivers were reluctant to take the locomotive over the new bridge.
Many passengers on the line in the 21st century are unaware of the significance of the “breakwater” they see as they look down, nor the fact that the new bridge is partially constructed from the salvaged remains of the old. William McGonagall became Scotland’s most unlikely poet based on his one famous work written about the night of ‘The Tay Bridge Disaster’, a poem so epically atrocious, it has been the subject of much fun and jest, most notably being read aloud on the high ground above Dundee overlooking the Tay Bridge by Billy Connolly, in a blinding snow-storm (available on Youtube!).