How many tunnels are there under the river thames

Within this narrow space three miners worked on their knees, one hewing at the face with his pick, another clearing away the sodden earth, the third shoring up the drift with timbers. Working conditions during the six-hour shifts were appalling; the men were soaked with sweat and river water, no one could stand or stretch, and the tunnel was so poorly ventilated that the fetid air sometimes extinguished the candles. Nevertheless, the Cornishmen made progress, and by January Trevithick reported that his drift was within feet of the north bank of the Thames and that the pilot tunnel would be completed in a fortnight.

Then things began to go disastrously wrong. The miners hit quicksand, then water, this time in such quantity that nothing could stop waterlogged soil from gushing into the driftway. The men at the face fled the shaft just ahead of the flood. Correctly guessing that his tunnel had come too close to an unexpected depression in the bed of the Thames, Trevithick arranged for the hole to be plugged with large bags of clay dumped into the river. To the astonishment of his detractors, this seemingly desperate measure worked, and the tunnel was pumped dry.

Within days, however, it flooded again, and this time the Thames Archway Company had had enough. Its funds were exhausted, its chief engineer was sick from exposure to the river water, and all its efforts had proved only that a passage under the river at Rotherhithe exceeded the limits of contemporary mining technology.

At that time, the only machines used in mines were pumps. It took a man of genius to recognize that a different sort of machine was needed—a machine that could both prevent the roof and walls from collapsing and hold back any quicksand or water at the tunnel face. Brunel was a tiny, eccentric man, impractical in his private life but an intensely able innovator.

This last had cut the cost of producing rigging pulleys by 85 percent. After he secured a number of contracts to supply pulleys to the Royal Navy, the Frenchman found himself relatively wealthy despite his lack of business acumen. Marc Brunel, father of the celebrated shipbuilder and railway engineer Isambard, was a notable engineer in his own right.

Image: Wikicommons. Examining the wood through a magnifying glass, he observed that it had been infested with the dreaded teredo, or shipworm, whose rasping jaws can riddle a wooden ship with holes. His insight led him to invent a device that has been used in one form or another in almost every major tunnel built during the last years: the tunneling shield. It consisted of a grid of iron frames that could be pressed against the tunnel face and supported on a set of horizontal wooden planks, called poling boards, that would prevent the face from collapsing.

The frames were divided into 36 cells, each three feet wide and almost seven feet tall, and arranged one atop another on three levels. The shield was topped by sturdy iron plates that formed a temporary roof and protected the miners as they worked.

Instead of hewing away at a large and exposed surface, they would remove one poling board at a time and hack out a mailbox-shaped hole to a predetermined depth—say nine inches.

Then the board would be pushed into the hole and screwed back into place before the next one was removed and the whole process begun again. When the miners in a cell had excavated the earth behind all of their boards, their frames could be laboriously jacked forward those nine inches.

In this way, the whole ton tunneling machine could move inexorably and safely on while masons trailed behind, shoring up the newly exposed tunnel with bricks. Photo: Wikicommons. Soil samples were taken beneath the riverbed, and Brunel was advised to stick close to the muddy river bottom, where he could expect clay, rather than risk striking quicksand by going deeper. When he began work on his tunnel in , the shaft that was sunk in dingy Rotherhithe was only 42 feet deep, and it was planned to pass within seven feet of the river bed in places.

The hazards of such an operation soon became apparent. At first, it was primarily a pedestrian tunnel until purchased by the East London Railway and turned into rail tunnel but eventually closed as other Underground and Overground lines became more prominent, though it was periodically reopened and used over the years.

Closed for good, there Brunel Museum now exists in the entrance at Rotherhithe. Coming at the tail end of the century, the Greenwich Foot Tunnel began in and finished in It was designed by Alexander Binnie and commissioned by the London County Council to replace a ferry that helped workers get from South London to the docks.

Repaired and refitted several times during its history, it still sees use by bicyclists and pedestrians. Linking Tower Hamlets and Greenwich, Blackwall Tunnel was first constructed from , then a second tunnel added from This tunnel was also designed by Binnie and commissioned by the LCC. When vehicle traffic became too much for the original tunnel, the second one was built in the s.

Crossrail is an Underground tunnel designed to link London with Berkshire, Buckinghamshire, and Essex. Construction on the central tunnel began in , and a section of the line from Liverpool Street to Shenfield opened in , with the rest of Crossrail expected to open in This series of underground rail tunnels were the first of their kind when opened in Several different railways operated the various lines until they all merged as the Underground in the early 20 th Century.

Others are hidden away from the main roads, such as the one in Abbot Road in Poplar, which takes you under the Blackwall Tunnel approach road. Say you were going from the end of the M11 in north east London south, via the A12 to the A2 at Eltham in south east London; you would pass through no less than six tunnels.

Due to the redevelopment of London's Docklands there is a large cluster of road tunnels east of Tower Bridge. Coming north over Waterloo Bridge, you can head into an unusually narrow, one-way tunnel known as the Strand Underpass; until the s it was used solely by trams making their way to and from Kingsway. Near Canary Wharf, at Westferry Circus is another unusual tunnel — if it can be called a tunnel at all.

Many are accessible to both pedestrians and cyclists. Beech Street tunnel at the Barbican has pavements on both sides. We'll gloss over the fact that Londonist once branded it one of central London's most wretched streets. And believe it or not, you are still able to walk or cycle through one of London's oldest road tunnels: the Rotherhithe Tunnel. Personally, I wouldn't recommend it, what with the constant flow of traffic going past at just 20mph — and more than enough exhaust fumes to affect your lungs.

More palatable for pedestrians are the tunnels under the railway tracks leading to some of London's railway terminals, particularly those around Waterloo and London Bridge.