On most engineering projects there are challenges that arise.
At the Crossrail project one of those challenges came in the form of modernizing the Connaught Tunnel to meet the space needs for electric trains.
The tunnel dates back to 1878 and was used to connect the Victoria and Albert docks under the Connaught Passage.
Out of commission since 2006, the 550 meter tunnel needed to be deepened, widened and strengthened so that it could accommodate Crossrail trains and overhead line equipment. In the process of modernization teams had to remove 135 years of soot and coal within the tunnel; and drain 13 million liters of water from the dock to allow access from above to deepen, widen and strengthen the central section of the tunnel.
“At Connaught we have performed what I call ‘open heart surgery’ on this Victorian tunnel," said Bechtel's Linda Miller, Connaught Tunnel Project Manager. "[We] not only brought it back to life, but turned it into a 21st Century piece of railway.”
Connaught is the only existing tunnel that will be re-used for Crossrail. When open up to 12 trains an hour in each direction will pass through the tunnel, reducing travel times significantly.
Here's a tour of the Connaught Tunnel with Bechtel's Linda Miller.
Video courtesy of Crossrail