For travelers who believe the journey should be as extraordinary as the destination, few experiences on Earth compare to Argentina’s legendary Tren a las Nubes — the “Train to the Clouds.”
This is not simply a scenic railway. It is a high-altitude engineering masterpiece, a window into Andean history, and one of the most unforgettable days on our Buenos Aires to Lima – An Andean Expedition.
Here, in the remote high Andes of northern Argentina, railways climb where roads struggle, and landscapes feel closer to the sky than to the earth below.
The Tren a las Nubes forms part of the historic Trans-Andean Railway, an audacious early 20th-century project designed to connect Argentina with Chile across some of the world’s most formidable mountains.
Rather than relying on rack systems, engineers used spirals, switchbacks, tunnels, and towering viaducts to gain altitude gradually — a feat of elegance and ingenuity still admired by railway historians today.
While the original railway once stretched all the way to the Pacific, today’s Tren a las Nubes journey focuses on its most dramatic section: a breathtaking ascent through stark puna landscapes to the iconic Polvorilla Viaduct.
It is widely considered one of the highest and most spectacular rail journeys in the world.
Your day starts in the charming colonial city of Salta, where Spanish balconies and Andean culture meet. From here, we travel by comfortable vehicle through a landscape that grows steadily more dramatic — red rock formations, sweeping altiplano plains, and distant snow-dusted peaks.
By the time we reach San Antonio de los Cobres, at over 3,700 meters (12,100 feet), the air is thinner, the light sharper, and the sense of adventure unmistakable.
Here, the vivid blue train awaits.
As we settle into spacious carriages with wide panoramic windows, the real ascent begins.
The journey to the Polvorilla Viaduct is a moving panorama of high-altitude desert, vast skies, and silent mountain ranges stretching to the horizon.
The train glides across slender bridges, curves through tunnels carved into raw mountainsides, and rolls along narrow ledges where the land seems to fall away into infinity. Every turn reveals a new perspective — copper-colored valleys, distant volcanoes, grazing vicuñas.
Onboard, the atmosphere is calm and quietly exhilarated. There is time to absorb the scale of the landscape, to photograph, to simply look out the window in wonder.
At 4,220 meters (13,845 feet) above sea level, the Polvorilla Viaduct marks the journey’s spectacular climax.
This colossal steel structure rises 63 meters (over 200 feet) above the valley floor and stretches across a vast Andean canyon. When the train stops, passengers step out into a world that feels almost lunar — immense skies, crisp mountain air, and an overwhelming sense of scale.
Local artisans display handwoven textiles and crafts, offering a glimpse into the culture of the Andean highlands. Our guides share stories of the railway’s construction and the communities that still call this remote region home.
It is a place where time slows, and where many travelers find themselves quietly moved by the magnitude of both nature and human achievement.
Though the setting is wild and remote, the experience is thoughtfully managed. The train features comfortable seating, onboard refreshments, and support staff accustomed to high-altitude travel. Oxygen and medical assistance are available if needed, allowing you to relax and fully enjoy the experience.
This balance — true adventure with attentive planning — is what defines our journeys through the Andes.
The Tren a las Nubes is not an optional extra or a side excursion. It is one of the defining moments of our Buenos Aires to Lima – An Andean Expedition, a journey that links Argentina, Bolivia, and Peru through legendary railways, dramatic landscapes, and rich cultural encounters.
We include this unforgettable experience on both of our 2026 departures of the expedition. Because operations here depend on weather, altitude conditions, and limited capacity, advance planning is essential — and for many of our guests, this becomes one of the most talked-about days of the entire journey.
Standing on the Polvorilla Viaduct, watching the train curve across the high Andes under an endless sky, it becomes clear: this is more than a railway journey. It is a rare privilege — a chance to experience one of the world’s great engineering feats in one of its most remote and beautiful landscapes.
If the idea of crossing South America by legendary railways, culminating in Machu Picchu, stirs something in you, the adventure may be closer than you think.
Your seat to the clouds is waiting.
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