Tay Rail Bridge of Dundee "in respect of his meritorious services as engineer of the bridge. ..." On 20 June 1879, Queen Victoria crossed the bridge during her return south from staying at Balmoral; Bouch was presented to her before she did so. On 26 June 1879, he was knighted by the Queen at Windsor Castle. On the night of 28 December 1879 at 7.15 pm, the bridge collapsed after its central spans gave way during high winter gales. A train with six carriages carrying seventy-five passengers and crew, crossing at the time of the collapse, plunged into the icy waters of the
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