The Bernina Express

From Chur in Switzerland to Tirano in Italy, the Bernina Express is a narrow-gauge train that climbs to one of the highest points on the European rail network, crossing the Landwasser viaduct, and the views are spectacular. In the depths of winter, the five-hour ride is like a trip to Narnia; in the height of summer, it’s more Sound of Music.

• The route is part of an alternative journey from Zurich to Milan. Save money by booking through German Railways (bahn.de/en). For example, a ticket from Singen to Tirano costs from €29.90 bought in advance, rather than €80 if bought in Switzerland

Belgrade to Bar

Photograph: Alamy

Opened in 1976 (though building started in the 1950s) the 296-mile journey from the Serbian capital to Bar, on the Adriatic coast in Montenegro, goes up and over awe-inspiring mountains and across the Mala Rijeka viaduct (pictured), once the highest railway bridge in the world. There’s a daytime and a sleeper train – you’ll still see the best bits if you get up early.

• One-way ticket around €20, with some special offers at €9.90. Buy tickets at the station; they’re not available online

Chicago to San Francisco

The historic train station in Flagstaff, Arizona. Photograph: Alamy

This epic two-night, two-day trip takes in many of the US’s huge landscapes: the flatlands of Nebraska, the Mississippi (crossed on a massive girder bridge), the Rockies, the rapids of the Colorado Canyons, the multi-coloured rocks of Utah and, in California, the pine trees and snow-capped peaks of the Sierra Nevada. You go through the Donner pass where the Donner party of pioneers resorted to cannibalism in 19th century – but hopefully the dining car won’t run out so you won’t have to.

• Book well in advance and you could get a reclining seat for around $200, amtrak.com

The Northern Explorer

Photograph: Alamy

This 12-hour ride from Auckland to Wellington covers an amazing cross-section of New Zealand’s North Island, featuring rainforest, canyons, coastline and volcanoes, passing over incredible feats of engineering. There’s also an open-air viewing platform, great for taking photos.

• Around NZ$158 (£90), greatjourneysofnz.co.nz

Hanoi to Ho Chi Minh City

Photograph: Alamy

This 1,000-mile, two-night journey on the Reunification Express passes islands, stilted houses and stretches of rainforest. The best bit is the coastal stretch from Hue to Danang. It’s outside the tourist bubble and you’ll meet Vietnamese families.

• Book online at 12go.asia or baolau.com for single sleeper fares from around £29

Top tips from the expert

In Europe, the key resource is the German railway’s website bahn.de, which has an online timetable for most of Europe. Two other sites worth knowing about are loco2. com and trainline.eu. Both connect to the big four ticketing systems: German, French, Italian, Spanish. Trainline also now connects to the Austrian system, and Loco2 connects to the UK’s.

• For more information see Seat61.com