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Forth Bridge (railway)

2007 Schools Wikipedia Selection. Related subjects: Engineering; Railway
transport

   CAPTION: Forth Bridge

   Forth Bridge
   The Forth Bridge, viewed from the Fife side, straddling the Firth of
   Forth.
   Official name Forth Bridge
   Carries Trains
   Crosses Firth of Forth
   Locale Edinburgh and Fife, Scotland
   Maintained by Balfour Beatty under contract to Network Rail
   Design Cantilever bridge
   Longest span 2 of 521.3 m (1710 ft)
   Total length 2528.7 m (8296 ft)
   Clearance below 150 ft
   AADT 190 - 200 trains per day
   Opening date March 4, 1890

   The Forth Bridge is a railway bridge over the Firth of Forth in the
   east of Scotland, to the east of the Forth Road Bridge, and 14 km (9
   miles) west of Edinburgh. It is often, erroneously, called the "Forth
   Rail Bridge" to distinguish it from the Forth Road Bridge. The bridge
   connects Scotland's capital Edinburgh with Fife, and acts as a major
   artery connecting the north-east and south-east of the country.

History

   Forth Bridge at Night
   Enlarge
   Forth Bridge at Night

   Construction of an earlier bridge, designed by Sir Thomas Bouch, got as
   far as the laying of the foundation stone, but was stopped after the
   failure of another of his works, the Tay Bridge. On Bouch's death the
   project was handed over to Sir John Fowler and Sir Benjamin Baker, who
   designed a structure that was built by Sir William Arrol's company
   between 1883 and 1890. Baker - "one of the most remarkable civil
   engineers Britain ever produced" - and his colleague Allen Stewart
   received the major credit for design and overseeing construction work.

Construction

   The bridge is, even today, regarded as an engineering marvel. It is 2.5
   km (1.5 miles) in length, and the double track is elevated 46 m
   (approx. 150 ft) above high tide. It consists of two main spans of
   1,710 ft, two side spans of 675 ft, 15 approach spans of 168 ft, and
   five of 25 ft. Each main span comprises two 680 ft cantilever arms
   supporting a central 350 ft span girder bridge. The three great
   four-tower cantilever structures are 340 ft (104 m) tall, each 70 ft
   diameter foot resting on a separate foundation. The southern group of
   foundations had to be constructed as caissons under compressed air, to
   a depth of 90 ft. At its peak, approximately 4,600 workers were
   employed in its construction. Initially, it was recorded that 57 lives
   were lost; however, after extensive research by local historians, the
   figure has been revised upwards to 98 . As well as the large number of
   deaths, eight more men were saved by boats positioned in the river
   under the working areas.
   Forth Bridge
   Enlarge
   Forth Bridge

   Hundreds more were left crippled by serious accidents, and one log book
   of accidents and sickness had 26,000 entries. In 2005, a project was
   set up by South Queensferry Historical Society to establish a memorial
   to those workers who died during the bridge's construction. In North
   Queensferry, a decision was also made to set up memorial benches to
   commemorate those who died during the construction of both the rail and
   the road bridges, and to seek support for this project from Fife
   Council.
   The Forth road and rail bridges; the rail bridge is on the right.
   Enlarge
   The Forth road and rail bridges; the rail bridge is on the right.

   More than 55,000 tons of steel were used, as well as 18,122 m³ of
   granite and over eight million rivets. The bridge was opened on March
   4, 1890 by the Prince of Wales, later King Edward VII, who drove home
   the last rivet, which was gold plated and suitably inscribed. A
   contemporary materials analysis of the bridge, circa 2002, found that
   the steel in the bridge is of good quality, with little variation.

   The use of a cantilever in bridge design was not a new idea, but the
   scale of Baker's undertaking was a real pioneering effort, afterwards
   extensively followed in different parts of the world. Much of the work
   done was without precedent, including calculations for incidence of
   erection stresses, provisions made for reducing future maintenance
   costs, calculations for wind pressures made evident by the Tay Bridge
   disaster, the effect of temperature stresses on the structure, and so
   on.

Painting the Forth Bridge

   Forth Bridge, Edinburgh.
   Enlarge
   Forth Bridge, Edinburgh.

   Although modern trains put fewer stresses on the bridge than the
   earlier steam trains, the bridge needs constant maintenance. "Painting
   the Forth Bridge" is a colloquial term for a never-ending task (a
   modern rendering of the myth of Sisyphus), coined on the erroneous
   belief that, at one time in the history of the bridge, repainting was
   required and commenced immediately upon completion of the previous
   repaint. According to a 2004 New Civil Engineer report on contemporary
   maintenance, such a practice never existed, although it is the case
   that under British Rail management, and before, the bridge had a
   permanent maintenance crew.

   A contemporary repainting of the bridge commenced with a contract award
   in 2002, for a schedule of work expected to continue until March 2009,
   involving the application of 20,000 m² of paint at a cost estimate of
   £10M a year. This new coat of paint is expected to have a life of 20
   years, which should see the bridge free from painters for a good few
   years.

Relief

   There is a new rail link under construction between Kincardine and
   Stirling. This will divert coal trains from the bridge. Instead they
   will travel via Stirling to Longannet Power Station. With this, there
   is a possibility that freight restrictions will be lifted and the
   potential of increasing trains from 8tph (trains per hour) to 12 tph.

Popular culture

     * The bridge is featured prominently in a scene in Alfred Hitchcock's
       1935 film The 39 Steps and even more so in the 1959 remake.
     * The bridge long featured in posters advertising the soft drink
       Barr's Irn Bru, with the slogan: Made in Scotland, from girders
     * The bridge was lit up red for BBC's Comic Relief in 2005
     * A countdown clock to the millennium was placed on the bridge in
       1998.
     * The Bridge, a novel by Iain Banks, is mainly set on a fictionalised
       version of the bridge.
     * In Alan Turing's most famous paper about artificial intelligence,
       one of the challenges put to the subject of an imagined Turing test
       is "Please write me a sonnet on the subject of the Forth Bridge".
       The test subject in Turing's paper answers, "Count me out on this
       one. I never could write poetry".
     * The Kincaid Rail bridge in the video game Grand Theft Auto: San
       Andreas is based on this bridge. The designer, Rockstar North, is
       based in Edinburgh.
     * "Painting the Forth Bridge" is an expression used to indicate a
       never-ending (and maybe even somewhat pointless) task (see section
       above).
     * Sebastien Foucan, a French freerunner, cat crawled along one of the
       highest points of the bridge, without a harness, for the Jump
       Britain Documentary by Channel 4(UK)
     * Linus points out the bridge from the airplane in the 1980 Peanuts
       film, Bon Voyage, Charlie Brown (And Don't Come Back!) as they
       approached Heathrow Airport.

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