The endless, sleep-inducing clang of metal can make train journeys the perfect time for some shut-eye. But sometimes, it pays to stay awake and take in the sights outside your window. If pretty landscapes alone are not tantalising enough, how about some hair-raising thrills to complement your ride? Although not quite your theme park roller coaster, some trains make their way across such treacherous peaks, seemingly impossible bends and steep gradients the faint-hearted will cling onto their seat with trepidation. Here are seven scenic train rides that are exhilaratingly beautiful — and dangerous.

Tren a las Nubes, Argentina

Credit: CC BY-SA-2.0 / GFDL (Boaz Tzur, 2002)

Translated as “Train to the Clouds” in English, the Tren a las Nubes certainly lives up to its name. Reaching a height of 4,200 metres, this railway is one of the highest in the world and clouds are literally seen around the bridges and slopes that the train passes through. In fact, the train travels at such a great height that medical assistants are stationed on board in case passengers suffer from asphyxia. The 217 kilometre-long train journey takes passengers from the northwestern Argentinean city of Salta and ascents the Andes Mountains until the La Polvorilla Viaduct, the highest point in the trip. There are several death-defying moments where the train makes its way through two zig-zags and two spirals. Throughout the 16-hour journey, the train travels across the rocky landscapes of Quebrada del Toro, the La Polvorilla desert canyon, the ruins of the ancient city of Tastil in the Lerma Valley and the town of Campo Quijano, where it has become a tradition for locals to sound their horns when the train passes through.

Cumbres & Toltec Scenic Railroad, United States of America

Credit: CC BY-SA-2.0 / GFDL (Marcel Marchon, 2003)

One might probably recognise this railway from the opening scene of the film Indiana Jones and the Last Crusade. Beginning at Chama in New Mexico, the locomotive chugs its way across the meadows and forests around Wolf Creek. Before long, the train commences its arduous ascent of the Cumbre Pass, the highest mountain rail pass in the USA. After making a lunch stop at Osier in Colorado, the train continues its journey across the narrow tracks at the 800m-high Toltec Gorge. Looking at the steep drop down to the Rio de los Pinos, one can only shudder at the thought of the train derailing. The train also navigates a tight loop at Tanglefoot Curve, and runs across several high trestles along the way, including Ferguson’s Trestle that derived its name from a grisly suicide incident there. The railway cuts through the abandoned town of Sublette towards its final destination in Antonito, Colorado.

Flåm Railway, Norway

Credit: CC BY-SA-2.0 / GFDL (Karen, 2009)

This 20 kilometre-long railway is one of the steepest on earth. Throughout the year, the train plies the route between Myrdal in the mountains to Flåm in Aurlandfjord at a steep gradient of 5.5% for almost four-fifths of its journey. The many mountain spirals along the track are also engineering feats that make the ride an exciting one. At one stretch of the journey, the train passes through Nåli, the longest tunnel on the track, scales the Myrdalsberget mountains through 21 nail-biting hairpin bends and then passes through a horseshoe tunnel built on a cliff with a steep drop. During the hour-long journey, passengers will be treated to magnificent sceneries of buildings including the 17th-century Flåm chapel and the memorial stone of poet Per Sivle, as well as views of mountains, waterfalls, valleys, fjords, farms and woods, including the Vidmesnosi mountains and Rjoandefossen waterfall. The picturesque landscapes and challenging route make the Flåm Railway one of the most visited tourist attractions in Norway and certainly one not to be missed!

Glacier Express, Switzerland

Credit: CC BY-SA-3.0 / GFDL (Champer, 2010)

One of the slowest express trains in the world, the Glacier Express takes eight hours to travel from St. Moritz to Zermatt. Not that it is anything to complain about, because one would appreciate all the time in the world to admire the postcard-perfect landscapes of glaciers, valleys, waterfalls, hamlets, gorges, castles and vineyards. Get those cameras ready and snap away at the marvellous views of the Alps, the Rhone Valley, Rhine Gorge and the 17th-century Stockalper Castle with its onion-shaped domes. Halfway through the journey, the train begins its steep descent from Oberalppass, the highest part of the journey at 2,033 metres. The gradient reaches a maximum of 11% at certain parts of the journey, making you tremendously grateful for those slanted, no-spill wine glasses sold on board. With steep drops, spirals and breathtaking scenery, this slow train ride does provide sufficient adrenaline.

Nariz del Diablo, Ecuador

Credit: CC BY-NC-SA 2.0 (Routard05, 2008)

Also known as the Devil’s Nose, this stretch of railway from Riobamba to Sibambe has been dubbed the “most difficult railway in the world” due to the challenging engineering work that went into building the track. The track zigzags its way around a seemingly insurmountable near-perpendicular shelf of rock that this railway was named after (between Alausí and Sibambe). The train shuffles forward and backwards as it struggles to climb up the 800m wall of rock, with the track gradient reaching a steep 5.5%. Passengers were once allowed to ride on the roof of the train but this is no longer allowed due to safety reasons; two Japanese tourists died in 2007 in an accident involving a cable. The track is part of the longer Trans-Andean railway that travels across the Andes.

Darjeeling Himalayan Railway, India

Credit: CC BY-SA-3.0 / GFDL (A.M.Hurrell, 2005)

The Darjeeling Himalayan Railway may be popularly known as the “Toy Train”, but travelling in this train is no child’s play. The train passes through a series of reverses, tight loops and zigzags as it makes its 88-kilometre journey from New Jalpaiguri to Darjeeling. Agony Point, rightfully named so, is the tightest bend on this line and is just one of the many challenges that the vintage locomotive has to overcome. The world’s second highest railway station, Ghoom, lies along this track at a height of 2,258 metres above sea level, and the track slants at 5.5% such that the train has to make several reverses in order to move forward. Listed as a UNESCO World Heritage Site, the railway rewards travellers who brave the journey with stunning views of waterfalls, alpine forests, valleys shrouded in clouds, tea plantations, and the snow-capped peaks of the Kanchenjunga mountain range.

Kuranda Scenic Railway, Australia

Credit: CC BY-SA-3.0 / GFDL (spaceodissey, 2008)

If the other railway journeys seem to daunting, the Kuranda Scenic Railway offers great scenery but with less of the fear factor. Travelling from Cairn to Kuranda, this railway takes visitors through lush forests, roaring waterfalls and steep mountains. At 328 metres above sea level, constructing this 34-kilometre railway was no mean feat and several lives were sacrificed in the process. The train weaves its way through 15 tunnels, 98 bends, 40 bridges, a World Heritage tropical forest and the Barron Gorge. Along the way, the train makes three stopovers for tourists to alight and enjoy supreme views of the scenery.