Season 1

In this opening episode, Dan, Anita and Robert try commuting Mumbai-style, tackling 'super dense crush load' on the world's busiest commuter trains. With as many as 14 people crushed into a square metre, these trains are more than twice as crammed as the most crowded UK trains. Passengers hang from the sides of trains and cross the tracks, so they're in for quite a ride. John Sergeant heads to Darjeeling's steam-powered hill railway and reveals the historical connection between tea and trains. And our cameras are on board with the astonishing dabba wallahs - a crack team of couriers who deliver 200,000 home-cooked lunches to offices all over Mumbai.

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 km every day - that's the distance to the moon and back, four times. Anita joins passengers on a long-distance sleeper across India to discover who's travelling, what they pay for their tickets and what the conditions are like on board. The station team have just six hours to service trains after every journey. With trains measuring more than half a kilometre in length, this is a gargantuan task. Robert joins the team to watch this turnaround in action. And we go on board one of India's poshest tourist trains, where you can travel like a maharaja at a cost of £600 per night.

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. 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.

In this final episode, 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. Dan meets two eye witnesses to 2008's terror attacks that claimed the lives of 52 people at the station. He also takes a ride on Mumbai's newly built Metro to consider what the future could hold for the city's 5.5 million rail commuters. John Sergeant is in the Western Ghats, one of India's biggest mountain ranges, revealing the heavy human cost of building the line that connects Mumbai to the south and east of India.