Work to replace a notorious bridge branded a dangerous and dirty traffic bottleneck has begun after years of campaigning by residents.
The 100-year-old Petts Hill bridge on the Harrow-Ealing border is to be ripped out and a new railway section dropped in place to allow the road underneath to be widened from two lanes to four.
The taller, wider £10million bridge will make the busy route between South Harrow and Northolt safer for motorists, cyclists and pedestrians with added cycle lanes, more pavement space, better lighting, extra bus lanes and upgraded crossings that can be controlled by pedestrians.
Single lane road closures and temporary traffic lights will be in force from 9.30am to 3.30pm until August 3 while workers undertake preparatory work.
The construction of the new bridge's foundations will run from August 3 until November, with the bridge itself lifted into place over the Christmas period when the Chiltern Line can be shut.
Meanwhile, the improvements to the roads and pavements below will be completed by summer 2009.
The Petts Hill bridge upgrade is being jointly funded by Harrow Council, Ealing Council, Transport for London and Network Rail, which owns the bridge.
Contractor enterprisemouchel (CORR) is holding a public exhibiton of the plans at Petts Hill Primary School, in Newmarket Avenue, Northolt, on Friday and Saturday, July 18 and 19.