World's Greatest Train Journeys from Above

This episode looks at the Glacier Express which connects Swiss towns St Moritz and Zermatt

Canada's Winnipeg to Churchill train is filmed from above as it winds through snow-covered grasslands, Boreal Forest and the barren lands below the Arctic Circle

This episode follows the luxury El Chepe train from above and on the ground. The route is a wonder of Mexican engineering that took 100 years to build and winds through the world's largest canyon region, Copper Canyon.

This episode follows the Darjeeling Himalayan Railway, a steeply graded narrow-gauge line connecting the plains of New Jalpaiguri in eastern India to the foothills of the Himalayas in Darjeeling. Led by a century-old steam loco, it is filmed from above as it conquers the world's tallest mountain range.

The Ghan, Australia's most luxurious train, crosses an entire continent from Adelaide on the southern coast to the tropical landscape of Darwin in the north. On its two-day journey, it faces intense heat, the risk of collisions with wild animals and the threat of increasingly extreme weather events. An army of engineers must work around the clock to maintain The Ghan and its 3,000 km of track.

Norway's Bergen line, running from Bergen to Oslo, is filmed from the air as it passes along the fjords of Western Norway, rises to the snowy Hardanger Plateau, and descends through deep forests. Along the way, we learn how a dedicated team of people keep the line open in a challenging environment: clearing snow and ice, deterring wildlife, and repairing damaged trains.