Birmingham-based rail and bus operator has missed out on the contract to run the £1.4 billion Crossrail project in London.
National Express was competing with three other operators - Arriva, French transport firm Keolis through Go Ahead and eventual winner Hong Kong-based MTR Corporation.
The contract is for eight years with an option to extend to 10.
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National Express said in a statement to the stock exchange today: "We submitted a strong, customer-focused bid that we believe would have delivered an excellent service and a fair deal for taxpayers.
"We are naturally disappointed and will be seeking feedback on our bid from Transport for London.
"We retain a very positive future in rail in the 海角视频 and abroad. We have recently been awarded the 15-year Essex Thameside franchise and have submitted a strong bid to Transport Scotland to operate the ScotRail franchise.
"In addition, we have been shortlisted to operate the Berlin Ringbahn and will begin operating two, 15-year rail contracts in North Rhine Westphalia, Germany in December next year."
The £14.5 billion Crossrail project will see trains running from Reading, to the west of the capital, to as far east as Shenfield in Essex, with links to south London as well.
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It is due to open fully by the end of 2019. Transport for London said MTR was expected to employ around 1,100 staff with up to 850 new roles, creating many hundreds of jobs for local people.
MTR will start running the services from the end of May 2015 between Liverpool Street and Shenfield, taking over the stopping services currently operated by Abellio Greater Anglia.
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