The director's initial plan was to hire all the main actors with names starting with alphabet A. Amitabh Bachchan, Ajay Devgan, Akshay Kumar, Aishwarya Rai, Atul Kulkarni, Amrish Puri and Akshaye Khanna. However, Akshaye Khanna dropped out and was replaced with Tushhar Kapoor on short notice (hence the odd one out).
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.