The Forth Bridge was an engineering marvel when it opened, and it still carries up to 200 trains a day.
Corbis/Hulton-Deutsch Collection __1890: __The Prince of Wales (later King Edward VII) taps a golden rivet into place to open the Forth Bridge in Scotland.
Ferries had crossed the Firth of Forth to link Edinburgh to the north of Scotland since at least the 12th century. Engineers proposed bridges as early as 1818, and work finally began on a design by Thomas Bouch in the 1870s. That project stopped abruptly after Bouch's Firth of Tay suspension bridge blew down in a gale in 1879 while carrying a passenger train, killing 75 people.
John Fowler and Benjamin Baker submitted a design in 1881 for a cantilever bridge made of modern steel to carry rails across the Forth. Factories were built on site to cut and shape the steel, and a new town housed 4,000 workers.
Three 330-foot towers went up, each atop four separate foundations. The towers cantilevered out toward one another, not quite touching. Machinery hoisted two 350-foot truss spans into place to be supported by the ends of the cantilever arms. Result: two clear spans of 1,710 feet each and a total length of 5,350 feet, not counting the approaches.
The muscular design, with its massive cross-bracing and 58,000 tons of steel, was hailed as a triumph of Victorian engineering on its completion in 1890. Fowler's knighthood was upgraded to a baronetcy, and both Baker and head contractor William Arrol received knighthoods of their own.
But the Forth Bridge was also criticized as expensive (3.2 million pounds, or $500 million in today's money) and "unnecessarily" strong. One such critic would live to regret his words. Theodore Cooper's design for the Quebec Bridge over Canada's St. Lawrence River used much lighter structural members. It collapsed while under construction in 1907, sending 19,000 tons of steel into the river and killing 82 construction workers.
The Forth Bridge still has the world's second-longest cantilever spans, and trains still run over it every day. It was renamed the Forth Rail Bridge after completion of the Forth Road Bridge (a nearby suspension span) in 1964.
The rail bridge has a firm place not only in British engineering and transportation, but in folklore. The bridge is the scene of a thrilling chase in Alfred Hitchock's 1935 film, The 39 Steps. And then there's the children's riddle: What would they do if the Forth Bridge collapsed? Answer: Build a fifth.
(Source: The Book of Bridges*, by Martin Hayden; various websites.)*
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