Britain’s high-speed rail network HS2 could have another 9km of tunnel added to its alignment under London. HS2 Ltd will recommend that High Speed Two (HS2) be tunnelled between Old Oak Common and Northolt after HS2 Ltd investigated this suggestion from local residents and Ealing Council.
A study has recommended a tunnel as the best option for this section of the route because a surface route would have caused more disruption to traffic, cost as much or more than a tunnel, and would have taken 15 months longer to build.
Following the results of the study, HS2 Ltd is now recommending – and the Secretary of State for Transport is minded to take the option forward – a 9km bored tunnel between North Acton (near Old Oak Common) and Northolt. If adopted, this would mean the proposed route for HS2 would be in continuous bored twin tunnels from Old Oak Common to West Ruislip – making it the longest tunnel on the route at 14km. This would make the tunnel longer than any of the tunnels currently being built under London for Crossrail.
HS2 Ltd Community and Stakeholder Manager for London, Peter Fry, said: “The recommendation to build a tunnel through Ealing and Northolt shows what can be achieved by working with local people and that we value their input and suggestions.
“The study we commissioned found that for this specific section of the line, the cost of tunnel would be comparable with a route on the surface without the need to replace bridges and divert associated utilities.
“The proposed tunnel will be included as the preferred option in the draft Environmental Statement for the first phase of HS2, so the community and stakeholders will have the opportunity to respond to this proposal as part of the consultation in coming months.”
The original route of HS2 through north west London, as announced in January 2012, proposed following the little used, existing railway line along the Northolt corridor.
However, a comprehensive study has been completed looking at the effects of building a 9km tunnel through Ealing and Northolt compared with using the existing rail alignment next to the Central Line – taking into account 18 road bridge replacements needed for a surface route compared to the infrastructure required to accompany a tunnel, such as shafts. It found, following more detailed work undertaken by HS2 Ltd, the surface option involved greater design complexity, including replacing both spans of the Hanger Lane gyratory. A tunnel would also be an estimated 15 months quicker to build than a surface route.
The proposed tunnel under Ealing and Northolt will be consulted on as alongside the draft Environmental Statement, due to be published in coming months.
If the route is tunnelled, vent shafts would be needed between North Acton and Northolt; their proposed locations will be consulted on alongside the draft Environmental Statement.