Work to strengthen the Connaught Tunnel for use by Crossrail trains is now underway following drainage of 13M litres of water from the Royal Victoria Dock.
Construction of cofferdams in the dock has enabled the roof of the tunnel to be exposed for the first time since it was built 135 years ago and will allow essential improvement works to be undertaken to return the tunnel to rail use.
The work is needed to repair parts of the structure that are in poor condition and also to remove steel segments that were installed within the brick arch structures in the 1930s when the dock was deepened.
With water from the dock drained, a 20m long, 10m wide hole is being opened up in the crown of the tunnel to allow the steel work to be removed and other repairs undertaken. Waterproofing, installing water pumps and cleaning the 135 years of coal and soot from the bricks will also be undertaken to bring the tunnel up to standard ahead of the start of Crossrail services from 2018.