Travelling through the Quebrada del Toro gorge on the Tren a las Nubes, or Train to the Clouds, is an unashamedly touristic experience. Clambering from the station in Salta (it never exceeds 35 km/hr) to the magnificent Meccano-like La Polvorilla viaduct, high in the altiplano, the smart train – with a leather-upholstered interior, shiny wooden fittings, spacious seats, a dining car, a post office and even altitude-sickness remedies – was originally built to service the borax mines in the salt flats of Pocitos and Arizaro, 300km beyond La Polvorilla. The viaduct lies 219km from Salta, and on the way the train crosses 29 bridges and twelve viaducts, threads through 21 tunnels, swoops round two gigantic 360° loops and chugs up two switchbacks. La Polvorilla, seen on many posters and in all the tour operators’ brochures, is 224m long, 64m high and weighs over 1600 tonnes; built in Italy, it was assembled here in 1930. The highest point of the whole line, just 13km west of the viaduct, is at Abra Chorrillos (4475m). Brief stopovers near La Polvorilla, where the train doubles back, and in San Antonio de los Cobres, allow you to stretch your legs and meet some locals, keen on selling you llama-wool scarves and posing for photos (for a fee). Folk groups and solo artists interspersed with people selling arts, crafts, cheese, honey and souvenirs galore help while the time away on the way down, when it’s dark for the most part.
The train leaves (and returns to) Salta’s Ferrocarril Belgrano station once or twice a week from late March to early December, with more frequent departures in July. It’s a long day – the train departs Salta at 7am and gets back just before midnight – though many people now take the speedier bus back.