Failed design triggers horrific Tay Bridge terror

Although a bridge over the great estuary of the Tay had been planned for many years, it was not until a meeting of the North British Railway Company, in November 1869, that the dreams were finally turned into action. A proposed design by Thomas Bouch received overwhelming approval from shareholders. Bouch had constructed several bridges previously and had a reputation for building structures that were completed on time and within budget. Work began and soon the foundation stone of the structure was laid on 25 July 1871.

The bridge's construction involved sinking piers into the riverbed that would then be built upon with a structure of columns and girders to the height required. The bridge had 85 spans between the piers which, at the highest section, rose to 88ft (26.8 metres) above the river and were known as the "high girders".

The construction of such a mighty and unprecedented structure understandably encountered problems. In February 1877, a violent storm blew up and, as a boat approached the bridge to rescue some stranded workers, "…the whole sky was lighted up for a few seconds with great bursts of fire," The Scotsman reported at the time. "It was evident … that some serious disaster had befallen the bridge."

Two of the large girders, each weighing 200 tons, had been blown down. A degree of hubris was noticeably evident after this accident, as it was now felt that the event proved the bridge's strength rather than pointing out the fragility of its most critical sections.

One of the damaged girders was recovered, repaired and, astonishingly by today's standards, replaced on the bridge. This is pinpointed as a critical error as the weakened girder may have contributed to the later disaster. Nevertheless the bridge was ready on time and within budget and opened for rail traffic on 26 September 1877.

Less than two years after the bridge's opening, on 29 December 1879, a storm, estimated by observers to be around 10 or 11 on the Beaufort 0-to-12 scale, began to sweep across eastern Scotland.

In Edinburgh, the 4.15pm train to Dundee left on time, making its way north across Fife, before arriving at St Fort, the last station before the Tay Bridge crossing. There, 72 passengers were counted, which, along with the train's three crewmen, are accepted as being the disaster's final death toll. The train then made its way across the bridge, on time for its 7.20pm arrival. It would never arrive.

Only one eyewitness seems to have observed what happened from the southern end. Railway worker John Watt had been sheltering in a signalman's hut when the train set out. He watched the light on the guard's wagon until it was in the vicinity of the highest part of the bridge. Then Watt observed two events: the light was seen to "fall away" and bright flashes appeared from what he surmised was the front part of the train. He remarked to the signalman: "either the girders or the train is down."

Observers on the Dundee side reported a more dramatic sight: "Almost simultaneous with the entry of the train upon this part [the high girders section] of the bridge, a comet-like burst of fiery sparks sprang out as if forcibly ejected into the darkness from the engine. In a long visible trail, the streak of fire was seen till quenched in the stormy water below. Then there was absolute darkness on the bridge." Something had obviously occurred, but what?

James Roberts, locomotive superintendent along with the Dundee stationmaster, James Smith, went out onto the bridge to investigate. The winds were still extremely strong and they found that they had to crawl along the rails on all fours until they saw a terrible sight. The entire high girders section of the bridge had gone. Now there was no doubting the horrible truth. The train had plunged into the Tay and 75 persons had almost certainly lost their lives.