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
Dee Bridge disaster from external view. The Norwood accident in 1891 led to a review of all similar structures by Sir John Fowler, who recommended their replacement. Cast iron had been used very successfully in the Crystal Palace of 1851 and the Crumlin Viaduct in South Wales (built in 1857), but the first Tay Rail Bridge of 1878 failed catastrophically due to its poor use of the material, putting the cast iron lugs on the columns into tension. The Tay Bridge disaster stimulated engineers to use steel, as exemplified by the Forth Bridge of 1890. The Dee bridge was later rebuilt using wrought