The Forth Railway Bridge

© Roel Wieringa (http://www.cs.utwente.nl/~roelw)

The GRAAL project (http://is.cs.utwente.nl/GRAAL)  

University of Twente, the Netherlands

13 November 2004

 

This text in pdf format

 

The Forth railway bridge, which we use as the icon of the GRAAL project, is a masterpiece of 19th century engineering. It is located 14 km. west of Edingburgh, Scotland, and connects the villages of South Queensferry and North Queensferry. It was built in the 1880s to carry two tracks of the North British Railway.

 

In 1879, the Tay railway bridge collapsed, killing 75 passengers and crew. It was the worst train crash in history so far, and when North British Railways proposed a bridge over the even wider Firth of Forth, the public demanded a safe structure.. An earlier project to cross the Firth of Forth, for which foundations were laid in 1873, was cancelled and a safer structure was designed by Sir John Fowler (1817-98) and Sir Benjamin Baker (1840 - 1907). The bridge contains three cantilever towers, each 104 m high.. A cantilever is a beam projecting from a support, such as a wall or a tower, and ``hanging in the air'' at the other end. The beams sticking out from the towers of the Forth railway bridge are supported at the other end by diagonal steel tubes projecting from the top and bottom of each of the towers. The total length of the bridge is 2.5 km and it has a height of 46 m over high tide, so that ships of the time could pass under it at high tide.

 

It was the first bridge made primarily of steel. 57 people lost their lives building the bridge. The bridge contains 55.000 tons of steel, 18.122 tons of granite, 21.000 tons of cement, and 7000.000 rivets. The last rivet, gold-plated ansd inscribe to record the event, was driven in by the Prince of Wales (later King Edward VI). It was the most expensive bridge ever, costing £2.500.000. The bridge as definitely overengineered, and  not even the strongest winds will shake it. It was designed to stand up to wind forces as high as 56 pounds per square foot.

 

The poet and artist William Morris declared it ``the supremest specimen of all ugliness.'' How tastes can change. Today, the Forth railway bridge is a tourist destination and every weekend families are strolling along the Firth, eating fish and chips and admiring the massive, elegant structure of the bridge. The bridge is sometimes called the Eiffel tower of Scotland, and a postcard made during its construction explains why.

 

In the GRAAL project, the bridge is a symbol of the engineering to be done to connect the two domains of business and information technology. The bridge is also a symbol of the major task in IT, bigger even than designing new IT systems: Maintenance. The Forth  railway bridge is subject to the deteriorating forces of wind, rain, and salt water, and since construction finished more than 110 years ago, it has been under maintenance. Maintenance  is challenging, because the bridge must remain under operation continuously. The bridge is continuously repainted, keeping its architecture intact. This gives us a noble goal to strive for in software engineering.

Further reading

 

A quick search with Google yields numerous photographs and stories about the bridge. http://www.pbs.org/wgbh/buildingbig/wonder/structure/firth_of_forth.html lists the bridge as one of the wonders of the world, comparing it with Brooklyn bridge and the Golden Gate bridge. http://www.geo.ed.ac.uk/scotgaz/features/featurefirst1053.html gives touristic information. http://www.glasssteelandstone.com/UK/Scotland/EdinburghFirthofForth.html gives basic facts about the bridge's architecture. The article ``Forth Bridge'' (Retrieved October 13, 2004, from Encyclopędia Britannica Premium Service (http://www.britannica.com/eb/article?tocId=9034977) explains what cantilevers are.