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Published: 12th August 2013
The largest construction project in Europe, London’s Crossrail project, has many challenges to overcome and rail.co.uk looks at some of these and the extraordinary discoveries the Crossrail team has found.
Crossrail is a unique opportunity for archaeologists to look at London’s history and they have made many significant discoveries under London. The latest is a 9,000 year old tool-making factory in southeast London and is in addition to striking gold at Crossrail’s Liverpool Street station site and a human bone uncovered in the foundations of a Roman road!
Crossrail archaeologists discovered rare evidence of human habitation on the Thames dating back to 7,000BC at Crossrail’s tunnelling worksite in North Woolwich. They found a Mesolithic tool-making factory along with 150 pieces of flint including blades.
The Crossrail team think prehistoric Londoners used the location to test, divide and prepare river cobbles used to make flint tools then taking them elsewhere to complete the process.
Crossrail Lead Archaeologist Jay Carver said: “This is a unique and exciting find that reveals evidence of humans returning to England and in particular the Thames Valley after a long hiatus during the Ice Age. It is one of a handful of archaeology sites uncovered that confirms humans lived in the Thames Valley at this time. The concentration of flint pieces shows that this was an exceptionally important location for sourcing materials to make tools that were used by early Londoners who lived and hunted on Thames Estuary islands.”
“This location in the heart of Liverpool Street holds a rich deposit of archaeology that provides an insight into London’s history over the last 2,000 years. Work to relocate local utilities is providing us with a tantalising glimpse of important finds just a few metres below street-level. We plan to excavate the Bedlam burial ground next year and carefully remove up to 3,000 skeletons as well as excavate a wider area to unearth Roman London.”
Crossrail struck gold when it found a 16th Century gold coin used as a sequin or pendent similar to those worn by wealthy aristocrats and royalty. This was appropriately found in The City at Crossrail’s Liverpool Street station site - but 500 years ago this was not a wealthy area so why precious and expensive gold item was there is a mystery.
At the same site, Crossrail archaeologists are uncovering layers of London’s history including the 16th Century Bedlam burial ground and Roman London. An exceptionally well made Roman road has also been unearthed where a human bone and horseshoes have been found in this road. The bone may have come from a nearby Roman cemetery and was found in the layers of rammed earth, clay and brush wood which was used to construct the road.
The cemetery has been scoured by The Walbrook, a tributary of The River Thames and also washed skulls and other bones downstream. These may date back to 1st Century following a revolution and may be heads of Boudicca’s victims from this era.
The burial ground seems to have been used for fly tipping in the 1600s now giving up many examples of 17th Century crafts giving an understanding of how east London manufacturers made expensive crafts for wealthy Londoners. Rare and exotic tortoise shell and elephant teeth which were used to make crafts such as expensive fans for these well-off Londoners.
13 million litres of water has been drained from the Royal Victoria Dock enabling Crossrail to get into Connaught Tunnel from above to allow rebuilding of the 1878 built railway tunnel.
A hole has been made approximately 20 metres long and 10 metres wide to allow engineers access to strengthen, deepen and widen the central section of the narrow tunnel enough to accommodate Crossrail’s trains in five years.
Sections of the tunnel are in poor condition and some of it was narrowed 80 years ago to allow a deeper water depth in the dock. This work will be reversed and the hole in the crown of the tunnel will allow Crossrail to remove material more easily.
To allow this work to be undertaken, a cofferdam measuring 1300 sq. metres, the size of four tennis courts was installed to allow a section of the Royal Victoria Dock to be drained so that Crossrail workers can access the tunnel from above. 332 fish were removed and safely relocated on either side of the cofferdam!
Linda Miller, Connaught Tunnel Project Manager said: “The Connaught Tunnel is testament to the engineering skill of the Victorians, but after 135 years there’s a lot of work that needs to be done to get it ready for Crossrail . Now we’ve opened the top of the tunnel we’ll start the engineering equivalent of open heart surgery - widening and deepening the structure so that it can accommodate up to twelve trains an hour in each direction.”
When the southeast section of Crossrail opens, up to 12 trains an hour in each direction will run through the Connaught Tunnel, reducing journey times and supporting the wider regeneration of the Royal Docks. With Crossrail, the journey from Abbey Wood to Bond Street will be around 20 minutes quicker and passengers travelling to Heathrow will be able to shave around 40 minutes off their journey.
As well as widening and deepening the central section of the tunnel, the work at the site will include waterproofing, installing water pumps and cleaning the 135 years of coal and soot from the bricks.