Dewatering wells sunk ahead of works to widen the tunnel
Preparations underway to dismantle the Connaught Tunnel’s 130 year old pump house ahead of donation to Newham Council
Archaeological dig close to finishing a search for evidence of riverside settlements dating back 6,000 years.
Crossrail has begun drilling wells at Connaught Tunnel to draw down the water table ahead of works to deepen and widen the 130 year old tunnel in east London.
Once the wells are completed, drawing down of the water table will begin next month which is required ahead of works to widen and deepen the central section of the Connaught Tunnel so it can accommodate Crossrail’s larger trains. The water table is also being lowered to allow for the pump house shaft to be deepened by another seven metres to 25 metres in order for it to accommodate modern pumping equipment that will work to keep the tunnel dry.
During the coming weeks the 130 year old pump house will be removed brick by brick and will be donated to Newham Council. This attractive Victorian building is too small to accommodate the larger modern pumping equipment that will be installed as part of the tunnel’s major refurbishment. Demolition of the former North London Line station at Silvertown has now commenced.
Works in Connaught Tunnel are well underway with the ballast – loose stone ground cover – and rail tracks already removed. Major piling works are also underway at the western approach to the tunnel in order to strengthen the ground. Survey work for to identify potential unexploded ordnance from World War II has been completed in the tunnel’s western approach with the all clear given. Crossrail’s archaeologists have opened their fourth and final trench for the site, searching for possible evidence of human activity dating back 6,000 years.
Connaught Tunnel Project Manager Linda Miller said: “Works are progressing extremely well and we are on track for turning this Victorian railway tunnel into modern infrastructure that will service London well into the next century. Major works will begin early next year after the London Boat Show, which will include placing coffer dams in the passage between Royal Victoria and Royal Albert docks, pumping out the water and performing engineering open heart surgery to widen and deepen the central section of the tunnel.”
Connaught Tunnel in the Royal Docks was built in 1878 and was part of the North London Line until 2006. The tunnel will be extensively refurbished as part of works to construct Crossrail’s new Abbey Wood branch.
Sections of the existing tunnel are in a poor structural condition. In 1935, larger ships began scraping the bottom of the Royal Victoria Dock which sits above Connaught Tunnel. As part of work to deepen the dock, the central section of the tunnel was narrowed with brickwork removed and steel segments installed.
Crossrail originally planned to strengthen the central section of the tunnel by removing the existing steel linings and back filling the entire section with concrete foam. These tunnels would then have been enlarged by boring through the concrete to create tunnels large enough for Crossrail trains to pass. However, concerns about the structural integrity of the tunnel as a result of work in the 1930s to narrow the tunnel have led to a new approach which will involve workers digging down to the tunnel to undertake the enlargement work. This will be the first time the tunnel has been exposed from above ground since its construction in the 1870s.
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Notes to Editors:
Refurbishment of the Connaught Tunnel is being undertaken by Vinci Construction UK Ltd.
Refurbishment of the Connaught Tunnel includes major repairs to the 1km tunnel including widening of the 550 metres of twin tunnels at the centre, putting in new tracks, waterproofing, installing new water pumps and cleaning the 130 years of coal and soot from the bricks.
The SS Robin is one of the world’s oldest steamships and was built in east London. The ship’s trust is seeking a permanent berth in the Royal Docks and it is proposed the Connaught Tunnel pump house structure would form the quayside ticket office.
The total funding envelope available to deliver Crossrail is £14.8bn.
The Crossrail route will pass through 37 stations and run 118 km (73 miles) from Maidenhead and Heathrow in the west, through new twin-bore 21 km (13 miles) tunnels to Shenfield and Abbey Wood in the east. When Crossrail opens it will increase London's rail-based transport network capacity by 10%, supporting regeneration and cutting journey times across the city. Crossrail services are due to commence through central London in 2018.
Crossrail is being delivered by Crossrail Limited (CRL). CRL is a wholly owned subsidiary of Transport for London. Crossrail is jointly sponsored by the Department for Transport and Transport for London.