UK transport operator Arriva is in talks with French National Railway Societe Nationale des Chemins de fer Francais (SNCF) over a merger with France's public transport operator Keolis.
The talks, which are in their preliminary stage, are for a potential tie-up with all or part of Keolis' transportation business with Arriva.
The deal is aimed at creating a leading European transportation business with revenues of nearly £6bn ($8.4bn).
SNCF owns 44.5% of Keolis, with a consortium of French insurer Axa SA and Canadian investor Caisse depot et placement du Quebec holding a 52% stake and Keolis managers holding the remaining 2.5%.
Keolis has a staff of nearly 40,000 across 11 countries with operations in Europe, Algeria, Australia and Canada and in 2008 it carried nearly two billion passengers and recorded revenues of €3.3bn ($4.62bn).
In UK, the company is a minority shareholder in the Govia joint venture with Go-Ahead, which operates the Southern, Southeastern and London Midland rail franchises.