During a violent storm on Sunday 28 December 1879, the first Tay Railway Bridge collapse killing all on board. This is the setting Dr Sage and Professor Savant find themselves in this month’s episode, Of Trainwrecks and Heartbreaks.
On the evening of Sunday 28 December 1879, a violent storm was blowing virtually at right angles to the bridge. Witnesses said the storm was as bad as any they had seen in the 20–30 years they had lived in the area; one called it a ‘hurricane’, as bad as a typhoon he had seen in the China Sea. The wind speed was measured at Glasgow – 71 mph – and Aberdeen, but not at Dundee. Higher windspeeds were recorded over shorter intervals, but at the inquiry an expert witness warned of their unreliability, and declined to estimate conditions at Dundee from readings taken elsewhere. One modern interpretation of available information suggests winds were gusting to 80 mph.
Usage of the bridge was restricted to one train at a time by a signalling block system using a baton as a token. At 7:13 p.m. a train from the south slowed to pick up the baton from the signal cabin at the south end of the bridge, then headed out onto the bridge, picking up speed. The signalman turned away to log this and then tended the cabin fire, but a friend present in the cabin watched the train: when it got about 200 yards from the cabin he saw sparks flying from the wheels on the east side, this continued for no more than three minutes, by then the train was in the high girders; then “there was a sudden bright flash of light, and in an instant there was total darkness, the tail lamps of the train, the sparks and the flash of light all … disappearing at the same instant.” The signalman saw none of this and did not believe when told about it. When the train failed to appear on the line off the bridge into Dundee he tried to talk to the signal cabin at the north end of the bridge, but found that all communication with it had been lost.
Not only was the train in the river, but so were the high girders, and much of the ironwork of their supporting piers. Divers exploring the wreckage later found the train still within the girders, with the engine in the fifth span of the southern 5-span division. There were no survivors; only 46 bodies were recovered but there were 59 known victims. Fifty-six tickets for Dundee had been collected from passengers on the train before crossing the bridge; allowing for season ticket holders, tickets for other destinations, and for railway employees, 74 or 75 people were believed to have been on the train.
– from Wikipedia
The First Tay Bridge
Construction began in 1871 of a bridge to be supported by brick piers resting on bedrock. Trial borings had shown the bedrock to lie at no great depth under the river. At either end of the bridge, the bridge girders were deck trusses, the tops of which were level with the pier tops, with the single track railway running on top. However, in the centre section of the bridge the bridge girders ran as through trusses above the pier tops in order to give the required clearance to allow passage of sailing ships to Perth.
The bedrock actually lay much deeper than the trial borings had shown, and Bouch had to redesign the bridge, with fewer piers and correspondingly longer span girders. The pier foundations were now constructed by sinking brick-lined wrought-iron caissons onto the riverbed, and filling these with concrete. To reduce the weight these had to support, Bouch used open-lattice iron skeleton piers: each pier had multiple cast-iron columns taking the weight of the bridging girders. Wrought iron horizontal braces and diagonal tiebars linked the columns in each pier to provide rigidity and stability. The basic concept was well known, but for the Tay Bridge, the pier dimensions were constrained by the caisson. For the higher portion of the bridge, there were 13 girder spans. In order to accommodate thermal expansion, at only 3 of their 14 piers was there a fixed connection from the pier to the girders. There were therefore 3 divisions of linked high girder spans, the spans in each division being structurally connected to each other, but not to neighbouring spans in other divisions. The southern and central divisions were nearly level, but the northern division descended towards Dundee at gradients of up to 1 in 73.
– from Wikipedia
Images from the Disaster
The Bridge of Tay Disaster is still considered one of the worst in British railway history.