The Glacier Express climbs almost 5 km during its daily eight-hour journey on a route that challenges locomotives to their max, and yet is so beautifully engineered, the railway has been declared a UNESCO Heritage Site – one of only three railroads in the world with that honour. Running between Zermatt, at the foot of the famous Matterhorn, and the ski town of St. Moritz, the Glacier Express travels across the mighty Swiss Alps as it runs from one side of the country to the other.Up to 250,000 people take the train every year, which has been running this route since 1930, yet parts of the rail line have been in operation for more than 125 years. MIGHTY TRAINS explores the challenges of climbing such heights and the railroad that conquers them. The locomotives hauling this train are cutting-edge versions of old technology, using rack and pinion drives to pull the train up the steepest slopes on the route.