Ajay Devgn will be romancing Kangna Ranaut in Priyadarshans next film, that too in a speeding subway train from London to Glassgow. Novel, isnt it? Well, actually, Jan de Bonts thriller, Speed, inspires Priyadarshans film. De Bonts film was about a bomb in a speeding bus that would go off if the bus lost speed. But the difference in my film, says Priyan, is that weve shifted the terror attack from a bus to a train. The untitled thriller goes on floors on September . On choosing a train in London for shooting his film, Priyan says, Weve got permission to shoot at one of the London stations and inside a train. It took some effort but we did it. I dont think it wouldve made sense to shoot the film without actual locations and the train. The most unusual part of the film is the casting. While Manoj Bajpai (a first for Priyan) has been cast in a positive role as the engineer trying to control the trains speed, Ajay Devgn plays the terrorist. The last time he was cast in a negative role was in Raj Kumar Santoshis Khakee. Apparently Devgn recommended Kangna to Priyan. Says the director, Ive just signed Kangna opposite Ajay. Ive never worked with her or Ajay before. Tusshar Kapoor and Sameera Reddy have also been cast as terrorists. My other favourite Suniel Shetty is also there in a special role.