The Elizabeth line (formally Crossrail) will provide rail services from Reading and Heathrow to the west of the capital, to Shenfield and Abbey Wood in the east. It will increase central London’s rail capacity by 10% and directly link Heathrow Airport, the West End, the City of London, and Canary Wharf.
In joint venture with Atkins, we designed the 42km of bored tunnels. These tunnels run under central London as well as Tottenham Court Road, Custom House and Woolwich stations, and Plumstead sidings for Crossrail Ltd.
Separate from this joint venture, Arup’s engineers designed Canary Wharf station and Crossrail Place for Canary Wharf Contractors. We also supported Laing O’Rourke on Liverpool Street station and Costain Skanska joint venture on Bond Street station.
200 m long trains
1,500+passengers per train
200mpeople per year
Helping to shape major infrastructure
Our involvement in the Crossrail project extends from the early 1990’s, when we undertook the geotechnical site investigation for the entire route. After a lull in the project, from 2006 to 2009, we updated the proposal for the section between Royal Oak and Farringdon, and looked at how to save costs in joint venture with Atkins. We achieved significant cost reductions by simplifying the underground connections and refining the scope of Paddington, Bond Street and Tottenham Court Road stations. Learning from our work on HS1, we helped develop the tunnelling strategy, reducing the number of tunnel boring machines required.
Threading tunnels through a congested subterranean environment
The 42km of bored tunnels had to be navigated through London’s congested subterranean world, weaving around building foundations, London Underground tunnels and many other structures and utilities. At Tottenham Court Road, we threaded the tunnels over the Northern line and below the escalators for the London Underground station. This created only 700mm between the Elizabeth line and Northern line tunnels. We also designed the various railway track-forms within the tunnels. The impact of noise and vibration from trains on theatres and recording studios above the route had to be alleviated. We designed special ‘floating slab’, a track structure on springs to minimise the transmission of noise and vibration into the surrounding ground.
Tunnelling under central London
The mitigation of ground movement due to tunnel and station excavation formed a major part of our work. We undertook impact assessments on over 17,000 buildings, including existing railways, major utilities, and other assets including listed buildings. We also designed mitigation measures for buildings likely to be affected by the ground movement. These included adjustments to tunnelling construction methods and the use of compensation grouting and underpinning.