Located 9 miles (14 km) west of Edinburgh, the Forth Railway Bridge is a remarkable cantilever structure which is still regarded as an engineering marvel and is recognised the world over. The bridge was built to carry the two tracks of the North British Railway the 1½ miles (2.5 km) over the Firth of Forth between South Queensferry and North Queensferry, at a height of 46m (150 feet) above the high tide. It was inscribed as a UNESCO World Heritage Site in 2015.
The structure, with its three massive cantilever towers each 104m (340 feet) high, was designed by Sir John Fowler (1817-98) and Sir Benjamin Baker (1840 - 1907) and built by Sir William Arrol (1839 - 1913) at the cost of some £2½ million. The bridge is the world's longest multi-span cantilever bridge and held the record for longest span in the world for seventeen years.
An earlier project, that was to have been executed by Sir Thomas Bouch (1822-90) and for which a foundation stone had been laid in 1873, was quickly cancelled following the collapse of his Tay Rail Bridge in 1879. With new engineers appointed, a second and much-strengthened design was drawn up and construction began in 1883. After seven years, 55,000 tonnes of steel, 18,122 cubic metres (640,000 cubic feet) of granite, 8 million rivets and with the loss of 57 lives, the bridge was complete. At the opening ceremony on 4th March, 1890, the Prince of Wales (later King Edward VII) drove home the last rivet, which was gold-plated and inscribed to record the event. Amongst many appearances on screen and television, the bridge was the location for Robert Donat's daring escape from a train in the 1935 film The 39 Steps, directed by Alfred Hitchcock and based on John Buchan's classic novel.
A second crossing, the Forth Road Bridge, was built in 1964. However, the rail bridge remains in regular use, carrying the main east coast line over to Fife and eventually onwards to Dundee and Aberdeen, although the stresses placed on the bridge by modern trains are much less than their much heavier steam-powered predecessors.
'Like painting the Forth Bridge' became the cliched phrase for a never-ending task, which indeed was the case until Network Rail completed a £130-million ten-year programme to encase the bridge in a specialist glass-flake epoxy paint at the end of 2011. Retaining the bridge's distinctive red-ochre colour, this coating bonds to the steelwork, providing a virtually impenetrable layer which should last at least twenty years.