The film is currently being shot in London following extensive negotiations with the transport authorities, the Hindustan Times has reported.
Director Priyadarshan told the site: "It was imperative to shoot in an actual train to give the film a realistic touch. It wasn’t easy to get permission."
He added that the actors and crew had difficulties in getting work permits because the film was perceived to be about terrorism.
"It’s about a headstrong man (Ajay Devgan) wanting to show his power over the establishment and hence, holding a moving train to ransom," Priyadarshan said.