RAILTRACK has chosen Bechtel to programme manage its £800 million upgrade of the Thameslink network.
The appointment of the US firm will be formally announced next month but Railtrack has been working with the company since last week on the route, which runs from Bedford to Brighton via the City of London.
The company edged out bids from Fluor Daniel, Parsons Brinckerhoff and Brown & Root.
Bechtel's contract is believed to be worth about £40 million and will cover the next six years, finishing when the Thameslink upgrade is completed in 2006.
The programme manager's team is understood to be largely the same as was drafted onto the strife-torn Jubilee Line Extension.
An insider said: 'The JLE had its problems but Bechtel got it open.'
At the height of construction work Bechtel will have about 50 personnel working on the project.