River Tay River Tay The River Tay () is the longest river in Scotland and the seventh-longest in the United Kingdom. The Tay originates in western Scotland on the slopes of Ben Lui (), then flows easterly across the Highlands, through Loch Dochart, Loch Iubhair and Loch Tay, then continues east through Strathtay (see Strath), in the centre of Scotland, then southeasterly through Perth, where it becomes tidal, to its mouth at the Firth of Tay, south of Dundee. It is the largest river in the UK by measured discharge. Its catchment is approximately , the Tweed's is and the Spey's is
Tay Rail Bridge of the top of the section below. The joint was then secured by bolts through matching holes on lugs (Crumlin) or flanges (Belah) on the two sections. This 'spigot and faucet' configuration was used (apparently without machining) on some Tay Bridge pier columns, but on some the bolts were relied upon to ensure correct alignment. (In the event, the joints were made using undersized bolts. This gave greater tolerances when assembling the column, but the less positive alignment of the column joints as initially assembled and after any subsequent 'working' of the joint would have weakened the column). On the