Forth Railway Bridge

Infobox Bridge
bridge_name= Forth Bridge


official_name=
carries=Rail traffic
crosses=Firth of Forth
locale=Edinburgh, Inchgarvie and Fife, Scotland
maint=Balfour Beatty under contract to Network Rail
id=
design=Cantilever bridge
mainspan=2 of 521.3 m (1710 ft)
length=convert|2528.7|m
width=
height=
load=
clearance=
below=convert|150|ft
traffic=190 - 200 trains per day
begin=
complete=
open=March 4, 1890
closed=
toll=
map_cue=
map_

map_text=
map_width=
coordinates= coord|56.000421|N|3.388726|W|region:GB_type:landmark|display=inline,title
lat=
long=:"For the nearby road bridge, see Forth Road Bridge."

The Forth Bridge is a cantilever 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 central Edinburgh. It is often called the Forth Rail Bridge or Forth Railway Bridge to distinguish it from the Forth Road Bridge, but should correctly be referred to as the Forth Bridge. The bridge connects Scotland's capital Edinburgh with the Kingdom of Fife, and acts as a major artery connecting the north-east and south-east of the country. Described as "the one internationally recognised Scottish landmark", [Keay, J. & Keay, J. (1994) "Collins Encyclopaedia of Scotland". London. HarperCollins.ISBN 0-00-255082-2] it may be nominated by the British government as a UNESCO World Heritage Site. [ [http://www.historic-scotland.gov.uk/index/policyandguidance/world_heritage_scotland/world-heritage-uk-list.htm Historic Scotland - UK Tentative List] Retrieved 03.03.2008.] The bridge and its associated railway infrastructure is owned by Network Rail Infrastructure Limited.

History

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. Bouch had proposed a suspension bridge but the public inquiry into the Tay bridge disaster showed that he had under-designed the structure and mistakenly used cast iron, which weakened the entire structure. 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 & Co. between 1883 and 1890. It was built in steel alone, the first bridge to use that material. Baker – "one of the most remarkable civil engineers Britain ever produced" – and his colleague Allan 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 convert|1710|ft|m|abbr=on, two side spans of 675 ft, 15 approach spans of convert|168|ft|m|abbr=on, and five of convert|25|ft|m|abbr=on." [http://www.forthbridges.org.uk/railbridgefacts.htm Forth Rail Bridge Facts & Figures] ". Forth Bridges Visitors Centre Trust. Retrieved April 21, 2006.] Each main span comprises two convert|680|ft|m|abbr=on cantilever arms supporting a central convert|350|ft|m|abbr=on span girder bridge. The three great four-tower cantilever structures are 340 ft (104 m) tall, each convert|70|ft|m|abbr=on 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 convert|90|ft|m|abbr=on. 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. [cite news| publisher=BBC News| url=http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/5313128.stm| title=Rail bridge death toll increases| date=2006-09-04| accessdate=2007-05-16| ] Eight men were saved by boats positioned in the river under the working areas. 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 the Queensferry History Group 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.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 4 March 1890 by the Prince of Wales, later King Edward VII, who drove home the last rivet, which was gold plated and suitably inscribed. [ [http://www.geo.ed.ac.uk/scotgaz/features/featurefirst1053.html Overview of Forth Bridge] . The Gazetteer for Scotland. Retrieved April 21, 2006.] A contemporary materials analysis of the bridge, c. 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 pioneering effort, later 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.

Where possible, the bridge used natural features such as Inchgarvie, an island, the promontories on either side of the firth at this point, and also the high banks on either side.

The bridge has a speed limit of convert|50|mph|abbr=on for passenger trains and convert|20|mph|abbr=on for freight trains. The weight limit for any train on the bridge is 1,422 tonnes (1,442,000 kg) although this is waived for the frequent coal trains, provided two such trains do not simultaneously occupy the bridge. The route availability code is RA8, meaning any current UK locomotive can use the bridge, which was designed to accommodate heavier steam locomotives.

Up to 190–200 trains per day crossed the bridge in 2006. [" [http://www.forthbridges.org.uk/railbridgemain.htm The Forth Rail Bridge] ". Forth Bridges Visitors Centre Trust. Retrieved April 21, 2006.]

Maintenance

A structure like the Forth Bridge needs constant maintenance and the ancillary works for the bridge included not only a maintenance workshop and yard but a railway "colony" of some fifty houses at Dalmeny Station. The track on the bridge is of "waybeam" construction: 12 inch square baulks of timber 6 metres long are bolted into steel troughs in the bridge deck and the rails are fixed on top of these special sleepers known as waybeams. In 1992 the bridge was re-railed with standard BS113A rail (54 kg/m). Prior to 1992 the rails on the bridge were of a unique "Forth Bridge" section. Although modern trains put fewer stresses on the bridge than the earlier steam trains, the bridge needs constant maintenance, and this is currently undertaken by Balfour Beatty under contract to Network Rail. [" [http://www.balfourbeatty.co.uk/bbeatty/media/pr/2002/2002-05-28/ Balfour Beatty Awarded Forth Bridge Contract] ". Press Release. Balfour Beatty, 28 April 2002. Retrieved April 21, 2006.]

"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 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 an estimated cost of £13M a year. This new coat of paint is expected to have a life of at least 25 years. In 2008 the total cost was revised upwards to £180M, and projections for finishing the job to 2012. [cite web |url=http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/7250560.stm |title= Forth Bridge painting set to end |accessdate=2008-02-18 |format= |work=BBC News ]

In a report produced by JE Jacobs, Grant Thornton and Faber Maunsell in 2007 which reviewed the alternative options for a second road crossing, it was stated that the estimated working life of the Forth Bridge was in excess of 100 years. [ [http://www.transportscotland.gov.uk/reports/publications-and-guidance/road/j8512a-05.htm Forth Replacement Crossing - Report 1 - Assessment of Transport Network | Transport Scotland ] ]

Competition

The Forth Road Bridge is another popular crossing of the Firth.

In 2007, in a two week trial jointly funded by SEStran and StageCoach, a passenger hovercraft ran between Kirkcaldy and Edinburgh. [http://www.stagecoachbus.com/fife/forthfastinfo.html] . However, Stagecoach have indicated that they are uninterested in developing this into a service. [http://www.sestran.gov.uk/news/article.php?ID=12]

The new Stirling-Alloa-Kincardine rail link 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 10 tph (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". [Turing 1950]

The Kincaid Rail bridge in the video game "" is based on this bridge. The designer, Rockstar North, is based in Edinburgh.

The process of painting the bridge presumably inspired Tom Stoppard's radio play "Albert's Bridge".

Sebastien Foucan, a French freerunner, crawled along one of the highest points of the bridge, without a harness, for the "Jump Britain" documentary made by Channel 4.

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. The Forth Bridge is convert|273|nmi|km north of Heathrow, but is generally visible on the approach to Edinburgh Airport.

References

Further reading

* Charles Matthew Norrie (1956). "Bridging the Years - a short history of British Civil Engineering". Edward Arnold (Publishers) Ltd.
* Arnold Koerte, "Firth of Forth, Firth of Tay", Birkhauser Verlag (1992), ISBN 0-8176-2444-9
* New Civil Engineer 5th February 2004, page 18.
* Peter R. Lewis, "Beautiful Railway Bridge of the Silvery Tay: Reinvestigating the Tay Bridge Disaster of 1879", Tempus, 2004, ISBN 0-7524-3160-9.
* McKean, Charles, "Battle for the North: The Tay and Forth Bridges and the 19th Century Railway Wars", Granta Books, (August 7, 2006), ISBN 1-86207-852-1.

External links

* [http://www.forthbridges.org.uk/railbridgemain.htm Forth Bridges Visitor Centre Trust - Rail Bridge Main]
* [http://www.forthbridgememorial.org Forth Bridge Memorial]
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