Tay Rail Bridge with fast-running tides. Tay Rail Bridge The Tay Bridge carries the railway across the Firth of Tay in Scotland between Dundee and the suburb of Wormit in Fife. Its span is . It is the second bridge to occupy the site. Plans for a bridge over the Tay to replace the train ferry service emerged in 1854 but the first Tay Bridge did not open until 1878. It was a lightweight lattice design of relatively low cost with a single track. On 28 December 1879, the bridge suddenly collapsed in high winds. The incident is one of the greatest bridge-related
Tay Bridge disaster 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