Dan Snow, Anita Rani, Robert Llewellyn and John Sergeant are in India, exploring the world's busiest railway. From their base at the Chhatrapati Shivaji Terminus in Mumbai they reveal the science, systems and staff responsible for keeping this supersized transport system running to schedule.

Dan Snow, Anita Rani and Robert Llewellyn examine the role the Chhatrapati Shivaji Terminus in Mumbai plays in long-distance travel across India. The country's rail passengers travel three million kilometers every day - that's the distance to the moon and back, four times.

Dan Snow, Anita Rani, Robert Llewellyn and John Sergeant go behind the scenes to reveal the hidden areas of the Chhatrapati Shivaji Terminus station unseen by commuters.

Dan Snow, Anita Rani, Robert Llewellyn and John Sergeant consider the challenges faced by the Chhatrapati Shivaji Terminus in Mumbai and ask what the future holds. Nine people a day die on Mumbai's railway lines. Anita tackles the railway's head of safety on the measures they're taking to reduce this fatality rate.