Thames Tunnel

The Thames Tunnel is an underwater tunnel, built beneath the River Thames in London. 35 feet wide (11 m), 20 feet (6 m) high and 1,300 feet (396 m) long, it runs between Rotherhithe and Wapping at a depth of 75 feet (23 m) below the river's surface at high tide. It was originally designed for, but never used by, horse-drawn carriages and was most recently used by trains of the London Underground's East London Line, although services have been suspended since 23 December 2007 for conversion of the line to become part of the London Overground network by 2010. It was the first tunnel known successfully to have been constructed underneath a navigable river [cite web
title = Thames Tunnel Construction
publisher = Brunel Museum
url = http://www.brunel-museum.org.uk/tunnel_construction.aspx
accessdate = 2008-08-31] ,and was built between 1825 and 1843 using Marc Isambard Brunel's newly invented tunnelling shield technology, by him and his son Isambard Kingdom Brunel.

History and development

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.John Timbs, "Stories of Inventors and Discoverers in Science and the Useful Arts", p. 287. Kent, 1860]

In 1805-1809 a group of Cornish miners, including Richard Trevithick, attempted to dig a tunnel further upriver between Rotherhithe and Wapping but failed because of 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 (305 m) of a total of 1,200 feet (366 m) had been dug.Denis Smith, "London and the Thames Valley", p. 17. Thomas Telford, 2001] However, even if it had been completed its usefulness would have been questionable; it only measured 2-3 feet by 5 feet (61-91 cm by 1.5 m), far too small for passenger use.

The failure of the Thames Archway project led engineers to conclude that "an underground tunnel is impracticable". [Nathan Aaseng, "Construction: Building the Impossible", p. 28. The Oliver Press, Inc., 1999] However, the Anglo-French engineer Marc Brunel refused to accept this conclusion. 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.

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.

The first step taken was the construction of a large shaft on the south bank at Rotherhithe, 150 feet (46 m) back from the river bank. It was dug by assembling an iron ring 50 feet (15 m) in diameter above ground. A brick wall 40 feet (12 m) high and 3 feet (91 cm) 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. 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 pastry cutter. The shaft became stuck at one point during its sinking as the pressure of the earth around it held it firmly in position. Extra weight was required to make it continue its descent, a total of 50,000 bricks were added as temporary weights. It was realised this problem was caused because the shaft was cylindrical, years later when the Wapping shaft was built it was slightly wider at the bottom than the top. This non-cylindrical tapering design ensured it did not get stuck. By November 1825 the Rotherhithe shaft was in place and tunnelling work could begin.

The tunnelling shield, built at Henry Maudslay's Lambeth works 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 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 sewage laden water seeping through from the river above. This sewage gave off methane gas which was ignited by the miner's oil lamps. 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 (3-4 m). To earn some income 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. 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 flooded again the following year, on 12 January 1828, when six men died and Isambard narrowly escaped drowning. Isambard was sent to Clifton in Bristol to recuperate where he heard about the competition to build what became the Clifton Suspension Bridge.

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 construction.

When work resumed in February 1836, a new shield had to be installed. Impeded by further floods, fires and leaks of methane and hydrogen sulphide 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:cquote|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,
When the Thames forced a gap,
And made it fit haunt for an otter,
Has proved that your scheme
Is no catchpenny dream;—
They can't say "'twill never hold water." [James Smith, "The Thames Tunnel", in "Memoirs, Letters, and Comic Miscellanies in Prose and Verse, of the Late James Smith", p. 185. H. Colburn, 1840]

The Thames Tunnel was fitted out with lighting, roadways and spiral staircases during 1841–1842. An engine house on the Rotherhithe side, which now houses the Brunel Museum, was also constructed to house machinery for draining the tunnel. The tunnel was finally opened to the public on 25 March 1843.

Pedestrian 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 exceeding its initial cost estimates. Proposals to extend the entrance to accommodate wheeled vehicles failed owing to cost, and it was only used by pedestrians. It became a major tourist attraction, attracting about two million people a year, each paying a penny to pass through,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] and 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". 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 transport artery:cquote|Amongst the blocks of buildings [in Wapping] that separate the street from the river, we notice an octagonal edifice of marble. We enter by one of several great doors, and find ourselves in a rotunda of fifty feet diameter, and the floor laid in mosaic work of blue and white marble. The walls are stuccoed, around which are stands for the sale of papers, pamphlets, books, confectioners, beer, &c. A sort of watch-house stands on the side of the rotunda next the river, in which is a fat publican, or tax gatherer. Before him is a brass turnstile, through which you are permitted to pass, on paying him a penny, and, entering a door, you begin to descend the shaft, by a flight of very long marble steps that descend to a wide platform, from which the next series of steps descends in an opposite direction. The walls of the shaft are circular, finished in stucco, and hung with paintings and other curious objects. You halt a few moments on the first platform and listen to the notes of a huge organ that occupies a part of it, discoursing excellent music.

You resume your downward journey till you reach the next story, or marble platform, where you find other objects of curiosity to engage your attention whilst you stop to rest. And thus you go down — down — to the bottom of the shaft eighty feet; the walls meanwhile, being studded with pictures, statues, or figures in plaster, &c. Arrived at the bottom, you find yourself in a rotunda corresponding to that you entered from the street, a round room, with marble floor, fifty feet in diameter. There are alcoves near the walls in which are all sorts of contrivances to get your money, from Egyptian necromancers and fortune-tellers to dancing monkeys. The room is lighted with gas, and is brilliant.

Now look into the Thames Tunnel before you. It consists of two beautiful Arches, extending to the opposite side of the river. These Arches contain each a roadsted, fourteen feet wide and twenty-two feet high, and pathways for pedestrians, three feet wide. The Tunnel appears to be well ventilated, as the air seemed neither damp nor close. The partition between these Arches, running the whole length of the Tunnel, is cut into transverse arches, leading through from one roadsted to the other. There may be fifty of them in all, and these are finished into fancy and toy shops in the richest manner — with polished marble counters, tapestry linings gilded shelves, and mirrors that make everything appear double. Ladies, in fashionable dresses and with smiling faces, wait within and allow no gentleman to pass without giving him an opportunity to purchase some pretty thing to carry home as a remembrancer of the Thames Tunnel. The Arches are lighted with gas burners, that make it as bright as the sun; and the avenues are always crowded with a moving throng of men, women and children, examining the structure of the Tunnel, or inspecting the fancy wares, toys, &c., displayed by the arch-looking girls of these arches ... It is impossible to pass through without purchasing some curiosity. Most of the articles are labelled — "Bought in the Thames Tunnel" — "a present from the Thames Tunnel".

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. [Susan Sellers / Sue Roe, "The Cambridge Companion to Virginia Woolf", p. 195. Cambridge University Press, 2000] 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:

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, a consortium of six mainline railways. which 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 accommodating horse-drawn carriages, provided a sufficient loading gauge for trains as well. The first train ran through the tunnel on 7 December 1869. In 1884, the tunnel's disused entrance shafts in Wapping and Rotherhithe were converted into Wapping and Rotherhithe stations 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 closed again from 23 December 2007 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.

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. A plaque could be seen above the stairs descending to the Rotherhithe platforms before the temporary closure. The plaque has been removed for safe keeping for the duration of the works.

Visiting

Nearby in Rotherhithe is the Brunel Museum 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. As of 2008 the museum is not running any tours through the Thames Tunnel by train as the East London Line is currently closed for major refurbishment and upgrade.

References

External links

* [http://www.ph.ucla.edu/epi/snow/1859map/thamestunnel_a2.html "Brief history during the Snow era"] , UCLA School of Public Health
* [http://www.brunel-museum.org.uk The Brunel Museum] - Based in Rotherhithe, London the museum is housed in the building that contained the pumps to keep the Thames Tunnel dry.
* [http://www.brunel-museum.org.uk/shop/shop_categories.asp Tunnel tour booking by the Brunel Museum]
* [http://www.flickr.com/photos/andreweason/151864640// Photos of a promotional book commemorating the opening of the tunnel]
*GBvosi|e=535100|n=180100|cty=10kent181|txt=This map, published in 1882, actually marks the tunnel

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place = River Thames
upstream=Tower Bridge|downstream=Rotherhithe Tunnel|bridge = Thames Tunnel
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