Originally built for economic and social reasons, it is now primarily of interest to tourists as a heritage railway, though cheaper tickets are also available for locals to use the train as transport.

The train runs four days a week, departing from San Antonio de los Cobres (where passengers arrive from Salta by bus) to La Polvorilla viaduct.

[10] Currently, the train leaves San Antonio station for the 13-hour,[4] 434-kilometre (270 mi) round trip to the Polvorilla viaduct, located 4,220 m (13,850 ft) above sea level.

[7] The possibility of a railway in the area began to be explored as early as 1889, and numerous studies were carried out up until 1916 analysing the feasibility of the line given the steep gradients and harsh terrain.

The line got its name in the early 1960s after students filmed a trip on the Salta-Antofagasta railway from inside the train carriages, often showing the vapor from the then-steam locomotive which – together with the cold mountain air – formed large vapour plumes.

Since then, the National and Provincial Governments rebuilt the line, replacing 60 km (37 mi) of tracks and granting a new concession to private company "Ecotren" to operate the Tren a las Nubes.

[25] For that refurbishing, coaches were remodeled by the Province along with freight transport company Belgrano Cargas, while diesel locomotives were repaired at Alta Córdoba workshops.