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 covered by a total of 85 spans. These spans are ordinary brick arches, backed by cement concrete and set on top of piers which are supported by pairs of columns. Wanting to avoid a repeat of the fate of the First Tay Bridge, a principal intention of the design is stability, followed in importance by measures to minimise the bridge's weight and the adoption of aesthetically pleasing shaping where possible without compromising on structural strength. The piers, which are primarily built from brick and concrete, are enclosed by a wrought iron caisson up to the low-water mark, above which a