River Tay naturally. To aid this process and improve the health and resilience of the population a further 28 beavers will be released in Knapdale between 2017 and 2020, however there are no plans at present to release further beavers into the Tay. In the 19th century the Tay Rail Bridge was built across the firth at Dundee as part of the East Coast Main Line, which linked Aberdeen in the north with Edinburgh and London to the south. The bridge, designed by Sir Thomas Bouch, officially opened in May 1878. On 28 December 1879 the bridge collapsed as a train passed
Tay Bridge disaster anomalously high because of peculiarities of the site (one of the highest points on the Wirral.<ref name="The Wirral Hundred/The Wirral Peninsula"></ref>): a wind pressure of would overturn railway carriages and such events were a rarity. (To give a subsequent, well documented example, in 1903 a stationary train "was" overturned on the Levens viaduct but this was by a 'terrific gale' measured at Barrow in Furness to have an average velocity of , estimated to be gusting up to .) A new double-track Tay Bridge was built by the NBR, designed by Barlow and built by William Arrol & Co. of