Dan Snow, Anita Rani, and Robert Llewellyn are in India, exploring the world's busiest railway. From their base at the Chhatrapati Shivaji Terminus, they reveal the science, systems and staff responsible for keeping this supersized transport system running to schedule.
This time they go behind the scenes to reveal the hidden areas of the 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 prepare to go on shift. It's a prestigious job in India with a salary around 7 times the national average. It takes around 12 years of training to qualify as a passenger train driver.
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 CST station control room when a train with a suspected fire on board threatens to bring evening rush hour to a halt. We witness how the control team divert and manipulate the traffic to keep delays to a minimum.
We also reveal the secret station workers who only come out at night, including the so-called "muck pickers" responsible for keeping the tracks free of rubbish. Show less