Tren a las Nubes

Route overview

The Tren a las Nubes, or Train to the Clouds, is a tourist railway service in northwestern Argentina that runs through the Andean altiplano. The route typically begins in the city of Salta, at an elevation of about 1,200 metres, and travels westward through the Quebrada del Toro and the Puna plateau. The journey culminates at the Polvorilla Viaduct, a spectacular steel trestle that curves across a deep gorge at approximately 4,220 metres above sea level. The total distance covered is roughly 217 kilometres, though the line is part of a longer branch that once connected to the Chilean border. The train operates on metre-gauge tracks, a common gauge in Argentina’s northern rail network. Notable features include the zigzag reversals at El Alisal and the long climb through the Toro gorge, where the train ascends steeply over a relatively short distance. The service is primarily aimed at tourists and runs on a seasonal schedule, offering a full-day excursion from Salta. The route is renowned for its extreme altitude, engineering feats, and starkly beautiful landscapes, making it a bucket-list experience for rail enthusiasts and travellers alike.

History of the line

The railway line that the Tren a las Nubes uses was originally part of the Ferrocarril General Manuel Belgrano, a state-owned network that aimed to connect Argentina’s northern regions with the Chilean border and the Pacific coast. Construction began in the early 20th century, with the section from Salta to San Antonio de los Cobres completed in 1948. The line was engineered by Richard Maury, an American engineer who designed a series of zigzags, tunnels, and viaducts to overcome the steep Andean terrain. The route was never fully completed to Chile; the final segment to Socompa was finished in 1948 but saw limited international traffic. Passenger services ceased in the early 1990s due to financial difficulties and track deterioration. In 1972, the Tren a las Nubes was inaugurated as a tourist train, gaining fame for its high-altitude journey. After a hiatus, the service was revived in 2008 under new management, with refurbished rolling stock and improved infrastructure. Today, it remains a symbol of Argentine railway heritage and a major attraction in the Salta region.

Landscape and scenery

The Tren a las Nubes traverses a dramatic and varied landscape that shifts from fertile valleys to arid high-altitude desert. Leaving Salta, the train passes through the Lerma Valley, with green fields and tobacco plantations. Soon it enters the Quebrada del Toro, a narrow canyon where the track hugs steep cliffs and crosses numerous bridges. The scenery becomes increasingly barren as the train climbs to the Puna, a high plateau characterised by sparse vegetation, colourful rock formations, and salt flats. The climax is the Polvorilla Viaduct, where the train pauses to allow passengers to admire the sweeping views of the Andean cordillera. Along the way, passengers may see vicuñas, llamas, and Andean condors. The altitude can cause breathlessness, but the panoramic windows and open-air observation decks provide unobstructed views. The journey offers a stark contrast between the lush pre-Andean valleys and the desolate beauty of the altiplano, making it one of the most scenic rail routes in South America.

Key stations and cities

The journey typically starts in Salta, a colonial city known for its well-preserved architecture and vibrant culture. The train departs from the Salta railway station, which has been restored to serve the tourist service. The first major stop is Campo Quijano, a small town that marks the entrance to the Quebrada del Toro. Further along, the train passes through El Alisal, where a zigzag reversal is performed to gain altitude. The highest point reached is near San Antonio de los Cobres, a remote mining town at about 3,775 metres. Here, passengers often have time to explore the local market and enjoy the Andean atmosphere. The final destination is the Polvorilla Viaduct, where the train stops for photographs. San Antonio de los Cobres serves as the practical end of the line for the tourist train, though the tracks continue towards the Chilean border. Other notable points include the Muñano station and the Abra Muñano, a mountain pass. The route connects several small Andean communities, offering a glimpse into life in this harsh environment.

Rolling stock and service

The Tren a las Nubes currently operates with a set of refurbished passenger coaches, many of which date back to the mid-20th century but have been modernised for tourist comfort. The train typically consists of several carriages, including standard seating, a dining car, and an observation car with large windows and an open-air platform. The locomotives used are diesel-electric, suited to the high-altitude conditions where oxygen levels are low. Onboard service includes meals and beverages, often featuring regional cuisine. The train is staffed by bilingual guides who provide commentary on the history, geography, and culture of the region. Due to the extreme altitude, the train carries supplemental oxygen for passengers who may feel unwell. The service runs on a seasonal schedule, usually from April to November, with departures several times a week. The journey lasts approximately 16 hours, departing early in the morning and returning in the evening. Reservations are required, and the train often sells out during peak tourist season. The experience is designed to be leisurely, with multiple stops for photography and exploration.

Technical facts and engineering

The railway line is a remarkable feat of engineering, built to metre gauge (1,000 mm) to navigate the challenging Andean terrain. The route includes 29 bridges, 21 tunnels, and 13 viaducts, with the Polvorilla Viaduct being the most iconic. This viaduct is 224 metres long and 70 metres high, supported by a curved steel structure that was assembled without the use of scaffolding. The line features several zigzags, where the train reverses direction to climb steep gradients. The maximum gradient is around 2.5%, which is steep for a non-rack railway. The highest point of the route is at an elevation of 4,220 metres near the Polvorilla Viaduct, making it one of the highest railways in the world outside of Tibet. The track passes through remote and geologically active areas, requiring ongoing maintenance. The original construction was carried out under difficult conditions, with workers facing extreme weather and altitude sickness. Today, the infrastructure is managed by the Argentine state, with periodic upgrades to ensure safety and reliability. The engineering heritage of the line is recognised as a national historic monument.

Frequently asked questions

What is the best time to ride the Tren a las Nubes? The train operates seasonally, generally from April to November, with the most comfortable weather occurring in the shoulder months of April-May and September-October. The rainy season (December-March) can cause service disruptions. How high does the train go? The maximum altitude reached is approximately 4,220 metres at the Polvorilla Viaduct. Passengers are advised to acclimatise in Salta for a few days before the journey to reduce the risk of altitude sickness. Is the train suitable for children and elderly passengers? The service is generally suitable for all ages, but the high altitude can be challenging for those with respiratory or heart conditions. Oxygen is available onboard, and the train makes frequent stops. The journey is long, lasting around 16 hours, so passengers should be prepared for a full day. Wheelchair accessibility is limited due to the historic nature of the carriages, but some assistance can be provided with advance notice. Overall, the Tren a las Nubes offers a unique and memorable experience for those who are reasonably healthy and prepared for the altitude.