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Bridges of the Forth 137
Elegant as the bridge is, its reinforced deck is less airy than that of the
Severn Bridge. However, the contrast with the railway bridge is marked: the
main span is longer, in contrast to the two railway lines the road bridge carries
two twenty-four feet carriageways and more. In the case of the railway bridge
much of the steelwork was assembled on site, whereas much of the Road
Bridge was prefabricated. In comparison with the rail bridge twenty-one and a
half thousand tons of steel were used; about half as much. However, some
things do not change much: Sir William Arrol and Company, together with
other distinguished bridge builders, participated in the building of the new
bridge.
Generally innovation in Scotland has taken place either too late, or with too
little impetus. The Kincardine-on-Forth Bridge ought to have been built a
decade before it was completed in 1936. It was a compromise. In 1919 Messrs
Mott, Hay and Anderson, who eventually built the Forth Road Bridge fortyfive
years later, produced a scheme for a road bridge at Alloa to relieve traffic at
Stirling Bridge, and in 1923 James Inglis Ker first proposed a suspension Bridge
at Queensferry. Mott, Hay, and Anderson undertook a survey completed in
1928. The Government was unwilling to pay the entire cost of either bridge,
and ‘The Silver Bridge’ at Kincardine, so called from the aluminium paint used
to maintain it, was built by Scotland’s relatively small pre-war local authorities
(the Burghs of Stirling, Falkirk and Dunfermline and Stirlingshire, Fife, and
Clackmannanshire), who cooperated with one another to build a bridge at the
lowest point where a bridge could be economically built. The Kincardine
Bridge was the cheapest solution, and, whereas an Alloa bridge would have
been of most benefit to Glasgow and the West, and a Queensferry bridge
would have served Edinburgh, it went some way towards serving both. The
bridge was designed by Sir Alexander Gibb and Partners, and built by the
august bridgebuilders Sir William Arrol and Company and others. It was not
until 1936 that the steel girder bridge was finished, and it was opened in 1937.
At the time it was built it was the longest road bridge in Britain, and the swing
bridge with the largest span in Europe. In order not to impede shipping the
swing span was built ‘open’; it had to be closed, rather than opened, before
traffic could use the bridge. The swing span, 110 metres long and weighing
2000 tons, provided two 45 metre openings for navigation. At the time the
bridge was built there was no question that provision had to be made for
shipping. Fifty years later in 1987 it was decided that the swing span could be
dispensed with and the ‘Silver Bridge’ was ‘closed’. It could be said of this
bridge that before it was opened it was closed, and before it was closed it was
opened, because before the machinery was shut down the span was swung
open one last time. The Kincardine Bridge is celebrated on cards of the thirties
which, as with the Forth Bridge, gave information about the bridge and details
of its pre-eminence.
In 1931 Jan Struthers summed up the attitude to the steel bridges of the
twenties and thirties in Punch: