Thames Tunnel
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The Thames Tunnel was the world's first underwater tunnel, built beneath the River Thames in London. 35 feet wide (11m), 20 feet (6m) high and 1,300 feet (396m) long, it runs between Rotherhithe and Wapping at a depth of 75 feet (23m) below the river's surface at high tide. It was originally designed for, but never used by, horse-drawn carriages and is currently used by trains of the London Underground's East London Line. It was built by Marc Isambard Brunel and his son Isambard Kingdom Brunel in the 19th century.
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[edit] History and development
[edit] Construction
At the start of the 19th century, there was a pressing need for a new land connection between the north and south banks of the Thames to link the expanding docks on both sides of the river. The engineer Ralph Dodd tried but failed to build a tunnel between Gravesend and Tilbury in 1799.<ref name="timbs">John Timbs, Stories of Inventors and Discoverers in Science and the Useful Arts, p. 287. Kent, 1860</ref>
In 1805-1809 a group of Cornwall miners, including Richard Trevithick, attempted to dig a tunnel further upriver between Rotherhithe and Wapping but failed due to the difficult conditions of the ground. The Cornish miners were used to hard rock and did not modify their methods for soft clay and quicksand. The "Thames Archway" project was abandoned after it caved in when 1,000 feet (305m) of a total of 1,200 feet (366m) had been dug.<ref name="smith">Denis Smith, "London and the Thames Valley", p. 17. Thomas Telford, 2001</ref> However, even if it had been completed its usefulness would have been questionable; it only measured 2-3 feet by 5 feet (61-91cm by 1.5m), far too small for passenger use.
The failure of the Thames Archway project led engineers to conclude that "an underground tunnel is impracticable."<ref>Nathan Aaseng, Construction: Building the Impossible, p. 28. The Oliver Press, Inc., 1999</ref> However, the Anglo-French engineer Marc Brunel refused to accept this verdict. In 1814 he proposed to Tsar Alexander I of Russia a plan to build a tunnel under the river Neva in St Petersburg. This scheme was turned down (a bridge was built instead) but Brunel continued to develop ideas for new methods of tunnelling.<ref name="timbs" />
Brunel and Thomas Cochrane patented the tunnelling shield, a revolutionary advance in tunnelling technology, in January 1818. In 1823 Brunel produced a plan for a tunnel between Rotherhithe and Wapping, which would be dug using his new shield. Financing was soon found from private investors including the Duke of Wellington and a Thames Tunnel Company was formed in 1824, with the project beginning in February 1825.<ref name="smith" />
The first step taken was the construction of a large shaft on the south bank at Rotherhithe, 150 feet (46m) back from the river bank. It was dug by assembling an iron ring 50 feet (15m) in diameter above ground. A brick wall 40 feet (12m) high and 3 feet (91cm) thick was built on top of this, with a powerful steam engine surmounting it to drive the excavation's pumps. The whole apparatus was estimated to weigh 1,000 tons.<ref name="timbs" /> The soil below the ring's sharp lower edge was removed manually by Brunel's workers. The whole shaft thus gradually sank under its own weight, slicing through the soft ground rather like an enormous cookie cutter. By November the shaft was in place and tunnelling work could begin.<ref name="smith" />
The tunnelling shield, built in Lambeth and assembled in the Rotherhithe shaft, was the key to Brunel's construction of the Thames Tunnel. The Illustrated London News described how it worked:
| The mode in which this great excavation was accomplished was by means of a powerful apparatus termed a shield, consisting of twelve great frames, lying close to each other like as many volumes on the shelf of a book-case, and divided into three stages or stories, thus presenting 36 chambers of cells, each for one workman, and open to the rear, but closed in the front with moveable boards. The front was placed against the earth to be removed, and the workman, having removed one board, excavated the earth behind it to the depth directed, and placed the board against the new surface exposed. The board was then in advance of the cell, and was kept in its place by props; and having thus proceeded with all the boards, each cell was advanced by two screws, one at its head and the other at its foot, which, resting against the finished brickwork and turned, impelled it forward into the vacant space. The other set of divisions then advanced. As the miners worked at one end of the cell, so the bricklayers formed at the other the top, sides and bottom.<ref>Illustrated London News, 25 March 1843</ref> |
The key innovation of the tunnelling shield was its support for the unlined ground in front and around it to reduce the risk of collapses. However, many workers, including Brunel himself, soon fell ill from the poor conditions caused by filthy water seeping through from the river above. When the resident engineer, William Armstrong, fell ill in April 1826 Marc's son Isambard Kingdom Brunel took over at the age of just 20.
Work was slow, progressing at only 8-12 feet a week (3-4m). To earn some money from the tunnel the company directors allowed sightseers to view the shield in operation. An estimated 600-800 visitors per day paid 1 shilling for the adventure.
The excavation was also hazardous. The tunnel flooded suddenly on 18 May 1827 after 549 feet had been dug.<ref name="smith" /> Isambard Kingdom Brunel lowered a diving bell from a boat to repair the hole at the bottom of the river, throwing bags filled with clay into the breach in the tunnel's roof. Following the repairs and the drainage of the tunnel, he held a banquet inside it.
The tunnel was flooded again the following year, 12 January 1828, when six men died and Isambard narrowly escaped drowning. Financial problems followed, leading to the tunnel being walled off in August. The project was abandoned for seven years, until Marc Brunel succeeded in raising sufficient money (including a loan of £247,000 from the Treasury) to continue work.<ref name="smith" />
When work resumed in February 1836, a new shield had to be installed. Impeded by further floods, fires and leaks of methane and hydrogen sulfide gas, the remainder of the tunnelling took another five and a half years, only being completed in November 1841. The extensive delays and repeated flooding made the tunnel the butt of metropolitan humour:
| Good Monsieur Brunel Let misanthropy tell That your work, half complete, is begun ill; Heed them not, bore away Through gravel and clay, Nor doubt the success of your Tunnel. That very mishap, |
The Thames Tunnel was fitted out with lighting, roadways and spiral staircases during 1841-1842. An engine house on the Rotherhithe side was also constructed to house machinery for draining the tunnel. The tunnel was finally opened to the public on 25 March 1843.<ref name="smith" />
[edit] Pedestian usage
Although it was a triumph of civil engineering, the Thames Tunnel was not a financial success. It had cost a fortune to build — £454,000 to dig and another £180,000 to fit out — far outrunning its initial cost estimates.<ref name="timbs" /> Proposals to extend the entrance to accommodate wheeled vehicles fell through because of the cost and it was only ever used by pedestrians. It became a major tourist attraction, attracting about two million people a year, each paying a penny to pass through,<ref name="drew">William Allen Drew, Glimpses and Gatherings During a Voyage and Visit to London and the Great Exhibition in the Summer of 1851, pp. 242-249. Homan & Manley, 1852</ref> and it even became the subject of popular songs. The American traveller William Allen Drew commented that "No one goes to London without visiting the Tunnel" and described it as the "eighth wonder of the world." <ref name="drew" /> When he saw it for himself in 1851, he pronounced himself "somewhat disappointed in it" but still left a vivid description of its interior, which was more like a underground marketplace than a working transport artery:
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Drew was perhaps charitable in his view of the tunnel, which came to be regarded as the haunt of prostitutes and "tunnel thieves" who lurked under its arches and mugged passers-by.<ref>Susan Sellers / Sue Roe, The Cambridge Companion to Virginia Woolf, p. 195. Cambridge University Press, 2000</ref> The American writer Nathaniel Hawthorne, writing in 1855, took a much more negative view of the tunnel when he visited it a few years after Drew:
| It consisted of an arched corridor of apparently interminable length, gloomily lighted with jets of gas at regular intervals ... There are people who spend their lives there, seldom or never, I presume, seeing any daylight, except perhaps a little in the morning. All along the extent of this corridor, in little alcoves, there are stalls of shops, kept principally by women, who, as you approach, are seen through the dusk offering for sale ... multifarious trumpery ... So far as any present use is concerned, the tunnel is an entire failure. |
[edit] Use as a railway tunnel
No doubt to the relief of the tunnel's investors, it was purchased in September 1865 by the East London Railway Company. The company — a consortium of six mainline railways — sought to use the tunnel to provide a rail link for goods and passengers between Wapping (and later Liverpool Street) and the South London Line. The tunnel's generous headroom, resulting from the architects' original intention of accomodating horse-drawn carriages, provided a sufficient loading gauge for trains as well. The first train ran through the tunnel on 7 December 1869.<ref name="smith" /> In 1884, the tunnel's disused entrance shafts in Wapping and Rotherhithe were converted into Wapping tube station and Rotherhithe tube station respectively.
The East London Railway was later absorbed into the London Underground, where it became today's East London Line. It continued to be used for goods services as late as 1962. The Thames Tunnel remains the oldest piece of the Underground's infrastructure.
In 1995 the tunnel became the focus of considerable controversy when it was closed for long-term maintenance. Its condition had deteriorated so severely that London Underground management publicly declared that if it could not be repaired the entire East London Line would have to be permanently closed. However, the proposed repair method was to seal it against leaks by "shotcreting" it with concrete, obliterating its original appearance. This led to a bitter conflict with architectural interests wishing to preserve the tunnel's appearance and disputing the need for the treatment.
Following an agreement to leave a short section at one end of the tunnel untreated, and more sympathetic treatment of the rest of the tunnel, the work went ahead and the route reopened — much later than originally anticipated — in 1998. The tunnel will close again from late 2007 / early 2008 to 2010 in order to permit tracklaying and resignalling for the East London Line extension, due to open in 2010. The extension work will result in the tunnel becoming part of the new London Overground and it will once again be used by mainline trains.
[edit] Influence
The construction of the Thames Tunnel showed that it was indeed possible to build underwater tunnels, despite the previous scepticism of many engineers. Several new underwater tunnels were built in the UK in the following decades: the Tower Subway in London, the world's first underground tube railway; the Severn Tunnel under the River Severn; and the Mersey Railway Tunnel under the River Mersey. All were built using refinements of Brunel's tunnelling shield, with James Henry Greathead playing a particularly important role in developing the technology. The historic importance of the tunnel was recognised on 24 March 1995, when the structure was listed Grade II in recognition of its architectural importance.<ref name="smith" /> A plaque can also be seen in the tunnel shaft at Rotherhithe tube station, commemorating the Brunels' achievement.
[edit] Visiting
Nearby in Rotherhithe is the Brunel Engine House which is open to visitors as a museum. It was originally built to house the draining pumps for the tunnel and has now been restored. During the year the museum organises "tunnel tours" when the lights in the tunnel are switched on and there is a rare chance to get a good view of the arches from a train.
[edit] References
<references />
[edit] External links
- "Brief history during the Snow era", UCLA School of Public Health
- The Brunel Engine House Museum, Rotherhithe
- Tunnel tour booking by Brunel Engine House
- Photos of a promotional book commemorating the opening of the tunnel
- Map and aerial photo of Thames Tunnel from Multimap.com
- Other map and aerial photo sources
- This map, published in 1882, actually marks the tunnel
| Next crossing upstream | River Thames | Next crossing downstream |
| Tower Bridge | Thames Tunnel Grid reference: TQ351801 | Rotherhithe Tunnel |
