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. Robert visits a city-sized repair facility where, every 18 months, train carriages are given their version of an MOT. He tries his hand at repairing seats and discovers that carriages are still painted by hand. Our cameras are on board with one of the train drivers - known as motormen - and are given privileged access to the lounge where they gather before going on duty. Anita heads onto the roads of Mumbai to see if commuting by road is any easier than by rail. But with an average speed of just 9 kmph, she discovers that progress is slow and hazardous by car. We're in the station control room when a train with a suspected fire on board threatens to bring evening rush hour to a halt, and we reveal the secret station workers who only come out at night. John Sergeant visits two rural stations that still operate historical systems for train control and discovers how a silver ball can keep passengers safe.