Rajkumar Santoshi narrated the story of the movie to Amar Singh (politician), who had arranged the meeting with Amitabh Bachchan and the film started with his blessings. Also, during the film's production he went out of his way to obtain permission to shoot on the train. Hence the reason Amar Singh is thanked in the opening credits.
Akshaye Khanna was due to play the role that eventually went to Tusshar Kapoor. He declined because of the scene where Amitabh Bachchan is forced to be slapped, and felt it was too disrespectful. Had he signed on, the main cast's first names would've all began with A - Amitabh, Akshaye, Akshay, Aishwarya, Ajay, Atul.