Government high speed rail project promoter HS2 Limited is to build part of the London section of the High Speed 2 (HS2) line to the North in tunnel rather than at ground level.
Work will involve constructing a 9km tunnel between Old Oak Common and Northolt in west London.
HS2 Ltd investigated the advantages of building a tunnel at the suggestion of residents in Ealing, where this section of line will run.
It concluded that a tunnel would cut construction time by 15 months, cause less traffic disruption and potentially save money.
Original plans would have involved demolishing 18 road bridges plus the Hanger Lane gyratory which connects the busy A40 and the A406 North Circular.
“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,” said HS2 Ltd London community and stakeholder manager Peter Fry.
The HS2 route through north west London announced in January 2012 proposed following a little used, existing railway line along the Northolt corridor.
Since then HS2 Ltd has carried out a comprehensive study, comparing the effects of building a 9km tunnel through Ealing and Northolt with using the existing rail alignment next to the Central Line.
It took into account the need for bridge replacements along the surface route compared to the infrastructure required to support a tunnel, including shafts.
The proposed tunnel will be included as the preferred option in the draft environmental statement for the first phase of HS2.