The list, which details the companies engaged in the Railway Procurement Agency's (RPA) tender pre-qualification process, also includes leading European operators such as Keolis, which runs the Metro in Lyon, France, and Luas operator Veolia.

Sources have said the high level of interest in the contract reflects that it is expected that the company that wins it will also obtain the right to operate the city's Metro West line, which is due to be completed in 2014.

Operators have also been attracted by the fact that, under the RPA's tendering process, they will have a say on the design of the system. During the process, operators will have to team up with an infrastructure and rolling stock builder to produce a single bid for the whole project. Although this is likely to simplify management, it will make it difficult to switch operators in future.

Other operators on the list are French operator Transdev, which runs ski services in the Alps; Paris transport authority RATP; ATM, which operates public transport in Milan; Britain's First Group and Dutch operator HTM. Leading rolling stock operators with Irish experience include Alstrom, which built the Luas trams, Spanish train builder CAF, which was responsible for Iarnrod Eireann's new MK4 rail carriages, and German industrial giant Siemens, which is responsible for the Dart refurbishment.