Travelling on one of the most photographed train routes in the world is far from expensive, and also far from comfortable. Departing from the mountainous city of Kandy, the train trundles through rainforest and lush palm jungle for ten hours, before pulling into the hill station of Ella, a backpackers' haven where you can stock up on essentials. About an hour outside Kandy, you enter tea country, which is what the region is known for. Book a second-class reserved seat a couple of days in advance at the local train station if you can - it's still very cheap and will at least guarantee you a seat. That said, the experience of peering out of the open door is equally unforgettable. In Ella, you can hike from the village and along the tracks to Nine Arches Bridge to get a stunning view of the old train going past. The train line was built in the 19th century, and hasn't changed much since.

Although trekking to Machu Picchu is the real way to see this Inca wonder, it may be that time, weather or fitness levels don't allow the luxury of travelling by foot. If that's the case, the stunning two-hour train journey from Ollantaytambo station is the next best thing. The Voyager is the least expensive of Inca Rail's options, coming in at around £100 for the round trip, and is also perhaps the most atmospheric. Comfy cream-colored seats and wide windows allow for a relaxing view of the sacred valley. The train also has an open-air observatory car with a bar.

Completed in the Eighties, this 1,972km rail route is one of the easiest ways into the Tibet Autonomous Region, and also a good way to acclimatise to the altitude. Gradually climbing into the Tibetan Plateau, the world's highest train line - dubbed the "sky road" - is the only train to have an oxygen-supply system in the carriages. You'll depart from the Qinghai Province city of Xining, carving through snowy mountains and past dazzling lakes, before arriving in Lhasa roughly 21 hours later.

Drift off to sleep once you've pulled out of Beijing's sprawling suburbs, and wake up well on your way to freezing Harbin in China's northernmost province, with ice crystals forming on the inside of the windows and -35C temperatures outside. The journey takes from seven to ten hours, depending on the time of day, so wrap up warm and pack a flask. Trains running on the Beijing to Harbin high-speed railway operate at over 200mph, hurtling past Shenyang and other northern cities. A highlight of Harbin during the bitter winter months is the dazzling Snow and Ice Festival, but the destination also makes for a refreshing, cooler break from Beijing in the heat of summer. Tickets for the sleeper train cost around £30.

If you don't fancy splashing a cool £10k to experience the uber-luxurious Golden Eagle Danube Express, which takes a week to glide through Eastern Europe, then the regular sleeper from Budapest to Istanbul is for you. What you lack in five-star comfort, you gain in a sense of adventure, as you traverse Romania and Bulgaria and on into the beautiful scenery of the Carpathian Mountains, before arriving in Turkey - a journey of around 21 hours. From the carriage, you can spot the 14th-century Bran Castle, inspiration for Count Dracula's creepy dwelling. A sleeper train departs from Budapest every night, with tickets costing roughly £41 for a berth in a four-person compartment.

Being such a major route from India's largest city down to the glorious palm-lined beaches of Goa does nothing to detract from the chaotic magic of this journey. The adventure starts at Chhatrapati Shivaji Terminus (commonly known as Victoria Terminus, or VT), Mumbai's main train station, a particularly ornate example of 18th-century Italian Gothic architecture. A Unesco-listed site in its own right, it's a wonder to behold. From here, the sleeper train heads south, passing waterfalls and verdant jungle on sometimes precarious-seeming cliff edges. The train to Margao, where Goa's main station is located, takes at least 13 hours. Travelling overnight is your best bet and still leaves plenty of time for gazing out the window. Tickets cost under £10.

Two daily trains travel between Mandalay and Lashio, a long, slow journey of around 280km through Myanmar's northern Shan State. The highlight is crossing the Goteik Viaduct, which was once the world's largest railway trestle and remains Myanmar's highest bridge. Completed in 1901, the epic structure offers magnificent views over the gorge and valley below. A remarkable feat of engineering, it's not for the faint-hearted.

Used as the filming location for JK Rowling's Hogwarts Express, the West Highland Line, on Scotland's spectacular west coast, cuts through some of the wildest and most diverse scenery in the British Isles. The journey takes just over five hours, with tickets costing £38. The train leaves busy Glasgow before heading north, passing Loch Lomond, Ben Nevis, Fort William and the Glenfinnan Viaduct (recognisable from the famous steam-train scenes in the Harry Potter franchise), and through great swathes of open countryside, before pulling into the fishing-port town of Mallaig.

Winding between the snow-sports havens of Zermatt and St Moritz, this eight-hour, Unesco-protected alpine route is a destination in itself. For more than 90 years, the glorious Glacier Express has invited guests to glide through Valais, Uri and Graubünden, skimming over 291 bridges and needling through 91 tunnels as they go. Bookended by the Matterhorn and Piz Bernina, it passes through world-class scenery: think the Rhône Glacier, the vertiginous Oberalp Pass, the curvaceous Landwasser Viaduct and the Rhine Gorge - the "Grand Canyon of Switzerland".