The UK government has decided to place a key section of the £50bn high-speed rail into a tunnel to minimise the disruption to residents and traffic and reduce construction time.
The decision will affect the area of Eiling and Northolt and will add additional 8 to 10 km to a previously planned under ground section running from and to West Ruislip in west London.
"We do not expect that many properties within the newly safeguarded area will be required for construction of the railway because the route will be in tunnel,” said UK transport minister Robert Goodwill, explaining the solution will reduce the construction time by 15 months.
"However, some land on the surface is affected, particularly for construction purposes, and owners of this land may be able to take advantage of the statutory blight provisions," Goodwill said.
In total, the tunnel section will be more than 14km long – the longest on the 225km section of the line to West Midlands, which is expected to be completed by 2026.
"A tunnel is the best solution for this part of the route,” said a spokesman for HS2 Ltd, a company responsible for delivering the project.
"By running our trains through a tunnel here we will save time during construction and there will be less disruption to residents, businesses and on local roads,” he said.
"Our station at Old Oak Common will be a major transport hub allowing passengers to switch between HS2 and the Crossrail connections to Heathrow and the Great Western Main Line."
Mr Goodwill also confirmed that another tunnel section of the line would be constructed taking the line into Birmingham using a new tunnel running under the M6 viaduct at Bromford.
HS2 said this would save school playing fields, public open space and community facilities, including Firs and Bromford Community Centre.