Bus and rail group National Express confirmed that it has received a second bid approach after rival FirstGroup walked away from a possible deal last night.National Express did not name the potential suitor, but the Times is reporting that Stagecoach was named by transport industry sources as the interested party."The group received an approach in connection with a possible offer for the group from another third party whose intentions are not yet known," National Express said."There can be no certainty that this approach will lead to an offer being made for National Express or as to the terms on which any offer might be made."First Group said after the close on Wednesday that it would be "inappropriate" to consider a formal offer for National Express because of uncertainties surrounding the business.Earlier this month, National Express said it would give up the running of the East Coast Main Line service after failing to renegotiate the cost of the franchise.