/> Kangna Ranaut and Ajay Devgn are back together in Priyadarshan's new thriller to be shot on an actual subway train speeding from London to Glassgow.

The film is inspired by Jan de Bont's 1994 thriller Speed about a bomb in a bus that would go off if the bus loses speed.

"But the film is not called Bullet Train. Nor is it inspired by that film. I don't know where this wrong news came from! It's inspired by Speed. The difference is that we've translocated the terror attack from a bus to a train " says Priyan as he prepares to shoot this untitled thriller from September 1 on a speeding train between London and Glasgow.

Says the director, "We've got permission to shoot on an actual London station and a train. It took some a effort. But we did it.I don't think it would've made sense to shoot the film without the actual location and 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 enigineer trying to control the train's speed so that the bomb doesn't go off, Ajay Devgn plays the ace- terrorist.

The last time he was cast in a negative role was in Raj Kumar Santoshi's Khakee.

Says Priyan, "I've just signed Kangna opposite Ajay. I've never worked with Kangna before. Tusshar Kapoor and Sameera Reddy have also been cast as terrorists. My other favourite Suniel Shetty is also there in a very special role."

Apparently Devgn recommended Kangna.

The film is written by Priyadarshan, along with Robin Bhatt (who also co-wrote Priyan's soon-to-be-released Aakrosh) and Aditya Dhar

Says Priyan, "I've never directed a thriller before. As for Khatta Meetha it's already done and out of my system.After 81 films how can I get excited about a release? But Khatta Meetha is not a comedy."