The Train d'Artouste: Europe's highest narrow-gauge train

Rattling 2,000m high through the French Pyrenees, the railway passes through one of France's wildest, most pristine landscapes.

A thick, heavy fog settled around our train as we trundled 2,000m above sea level along a serpentine track in the French Pyrenees. 

With little visibility ahead, there was a disorienting and quietly thrilling sense of uncertainty as the open-air Train d'Artouste – the highest narrow-gauge railway in Europe – rumbled daringly close to the mountain ledge and the vertiginous drop to the valley below. From my seat at the back of the train, I watched as the rail cars ahead disappeared into the clouds and mountain mist, making it difficult to anticipate the turns that swung us unexpectedly to the right one minute and then sharply to the left the next. 

It was a stark contrast to the first leg of my trip a few hours earlier under bright blue skies, when every turn brought new perspectives of the unspoilt, tree-dotted, rocky alpine landscape into sharp, unfiltered view. 

My journey had begun a few hours earlier as we passed through the damp and narrow Bear Tunnel (Tunnel de l’Ours), dodging droplets from the cave roof above. Moments later, we burst through the other end, temporarily blinded by the morning sun until our eyes adjusted to the lush, green Vallon du Soussouéou around us, the clouds below, and the backlit mountains in the distance.

"The particularity of our open-air trains is that you can fully enjoy the scenery," said Jean-Christophe Lalanne, the Train d'Artouste's station director, noting that the rail's maximum speed is only 18kph. 

A mountainous chain separating south-western France from north-western Spain, the Pyrenees has no shortage of adrenaline-inducing railways. There's the Train de la Rhune which climbs 905m to the summit of La Rhune and offers views of the ocean, and the Train Jaune that crosses through 19 tunnels and 40 bridges. But while researching French rail trips, I was most struck by the Train d’Artouste, not only for the precariously thin margins between the track and mountain's edge, but for the rare chance to experience the wind, sun, smells and sounds of the mountains at its most intimate, unimpeded by coach roofs or walls. 

The excursion starts at Lac de Fabrèges roughly 7km from the Spanish border, where passengers board a 10-minute gondola that climbs 1,900m to reach the departing train station. There, riders are greeted by cheerful red-and-canary-yellow carriages resembling oversized toy trains and settle in for the 10km, 55-minute one-way ride along the edge of the mountain that terminates at the Lac d'Artouste station. Passengers then alight to visit Lac d'Artouste and the surrounding mountains for either a half or full day before taking the return train back. Some serious hikers use it as the point of departure for multi-day hiking trips. 

During the train ride, the scenery unfolds to include pops of wild pink rhododendrons blooming in the green valley, mountain pine trees that grow at unexpected angles from the side of the cliff, cascading waterfalls and chubby marmots that take no notice of us. The open-air experience amplifies the clicks and clacks of the train as it travels over the tracks, akin to a loud metronome keeping the beat throughout the journey.

"Whether it rains, or it's sunny, every day is different," said train conductor Audrey Urieta, who has been operating the seasonal May-to-October trains for the past three years. "Even when the weather is bad, when there's fog or storms, there's always something beautiful to see. The landscapes and the light are different every day." 

It may be a sightseeing attraction now, but the Train d'Artouste was originally built to shuttle labourers and equipment, not tourists. At the end of the 19th Century, a priest and scientist who studied glaciers discovered Artouste, a glacial lake that had remained hidden deep within the mountains. Soon after, an ambitious idea was hatched to build a dam and harness the lake for hydroelectric power. Yet, facilitating access to this remote water source required building a railroad that could ferry both people and materials to the construction site. 

When construction began in 1921, some 2,000 men – mostly Spanish workers from across the border – used dynamite and pickaxes to blast tunnels and chip away at the limestone and granite rock face. The final track was laid in 1924 and carried goods and workers to and from the construction site for the next five years, where labourers toiled year-round in harsh conditions: one man was killed when a cable broke and decapitated him. 

The tracks were hastily dismantled once the dam was inaugurated in 1929, only to be rebuilt after operators realised they still needed it to maintain the dam (the train is still used for maintenance work today). But the local prefecture saw much more potential. By 1932, the construction of a gondola below and several new coats of paint turned an industrial train into a shiny new tourist attraction. The late 1960s saw the inauguration of the Artouste ski station, and in 1984, the Artouste-Fabrèges resort village opened a short walk from the gondola, attracting a steady stream of visitors to the train.

According to Dominique Krauskopf, author of the book The Most Beautiful Trains of France, tourist trains such as the Train d'Artouste "speak of the engineering prowess of the time", while revealing fascinating glimpses of a region's unique history and heritage. 

Every summer, for instance, the Train d'Artouste provides a unique vantage point for a remarkable pastoral tradition that dates back to the Middle Ages. At the beginning of July, herders move their sheep, cows, horses and goats up to higher mountain pastures where the animals graze on fresh grass and mountain wildflowers all summer before moving back to the low-lying farms in the fall – a practice known as transhumance. It's this terroir that gives Ossau-Iraty, the region's famous sheep's milk cheese, its signature nutty, floral aromas. A well-timed train booking means passengers can experience both a unique rail journey into the heart of one of France's wildest, most pristine landscapes, while witnessing an ancient Pyrenean tradition that remains an important part of rural life. 

This sky-high slow train ride may offer passengers easy access to the Pyrenees' rugged wilderness, but it also allows travellers to explore the region on foot.

The most popular train ticket is the Discovery package – a 3.5-hour experience that includes about an hour and a half of free time between rides to and from Lac d'Artouste. But I purchased the Escapade ticket, which allowed me to take the first train up at 10:00 and the last train back at 17:45 (that changes to 19:15 during the July-August high season).

My warm-up hike was the 20-minute trek to the dam, a monumental 27m-high concrete wall holding back an ancient, crystalline lake from the dry, fertile valley on the other side. A thick and fast-moving fog turned fellow hikers into ghostly silhouettes and obscured whole mountains, reminding us that up here, nature is a capricious shapeshifter. 

After brushing off the last crumbs of my tuna sandwich lunch alongside other picnickers, I tightened my hiking bootlaces and followed signs for the Lacs d'Arrémoulit trail. The 2.5-hour climb ends at the Arrémoulit mountain refuge (2,305m altitude) in the Pyrenees National Park, which straddles the French and Spanish border and features glacial lakes, floral meadows, caves, ravines and ancient peaks and valleys across. The area around the park's Mount Perdu includes two of Europe's largest and deepest canyons and is a Unesco World Heritage Site.  

The hike started slow and easy, with views of the turquoise Lac d'Artouste in my peripheral vision, and the grass-carpeted mountain peaks looming up ahead. The Pyrenees are older, and some say less dramatic, than the Alps, the higher, snow-capped mountain range to the east. But the mountain landscape here is arguably more rugged and unspoiled and boasts one of France's most biodiverse ecosystems: 3,000 plant species, and more than 4,000 animal species – including goat-antelopes, brown bears and Egyptian vultures. 

With the lake behind me, the climb began to get more challenging and my footing less sure as the trails seemed to grow narrower and rockier with the ascent. But each new step rewarded me with views of pink flowering mosses, pops of purple irises and butter-yellow Adonis flowers, and I followed them like breadcrumbs on a trail. 

When fatigue hit, I stopped to dip my hands in the cool mountain stream and brought my gaze upwards toward the many rushing waterfalls. I was deep in the mountains before I realised that time had escaped me, and though I was so close to the refuge, it was time to head back to the train. Truth be told, I was looking forward to the ride back, when I could prop up my feet and let the train do the rest of the work for me.

Back on board, I let the hypnotic metronome beat lull me into a trance and leaned into the twists and turns of the track. Under the fog of moody, mysterious skies, I contemplated how different the return journey felt and was reminded of the train conductor Urieta's words: no two journeys are ever alike.

Rail Journeys is a BBC Travel series that celebrates the world's most interesting train rides and inspires readers to travel overland.

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