Tren a las Nubes

The Tren a las Nubes runs on the old Salta to Antofagasta railway, an engineering feat built across the Andes in the first half of the twentieth century without a single rack or cable, climbing instead by zigzags and spirals cut into the mountainside. Its destination is the Viaducto La Polvorilla, a slender steel trestle 224 metres long and 63 metres high, standing on the bare puna at more than 4,200 metres, where the train pulls out onto the span and stops so passengers can look down into the ravine. The full journey today combines a bus leg through the Quebrada del Toro with the rail section from San Antonio de los Cobres, taking a long day out of Salta and passing from green valley to cactus canyon to the empty, dazzling high plateau.

What you actually see

• Viaducto La Polvorilla - the steel trestle at over 4,200 metres, the journey's climax.
• The Quebrada del Toro - the colourful canyon the route climbs on the way up.
• The puna - open altiplano with llamas, adobe hamlets and volcanic horizons.
• San Antonio de los Cobres - the high mining town where the rail section begins.

When to go

April to November for settled weather; services run on a seasonal schedule with fewer departures in winter and none on some dates. Book weeks ahead in high season. The whole day runs from early morning to late evening.

Honest expectations

It is a long, expensive day with many hours seated, and the altitude affects a good number of passengers; oxygen is carried on board for a reason. The train no longer runs the whole route from Salta, so part of the trip is by bus. Some travellers find the same landscapes better seen by car.

Nearby

San Antonio de los Cobres is on the route; Salta city is the departure point.