Nexus will continue to own all trains on the network
Bidders from China, Germany and Holland are among those vying to operate trains and stations on the Tyne and Wear Metro, it has been revealed.
Four bids have been shortlisted to take control of the network from 2010.
They include Hong Kong's MTR Corporation, Germany's DB Regio, Dutch-based Serco-NedRailways, as well as an in-house bid from Metro managers.
The successful bid will be announced in January 2010, with the contract running for nine years.
Current operator Nexus will continue to own all the trains, set fares, specify timetables and coordinate improvements to the network's 60 stations.
Unions have expressed concern at the process, claiming the network is being privatised.
Ken Mackay, director of rail and infrastructure at Nexus, said: "We had a great deal of interest from the UK and abroad in the Metro operations concession.
"We have narrowed that down to the four companies best placed to put in a strong bid and meet the high expectation of customer service and excellence Nexus demands for Metro passengers."