The famous narrow-gauge Tren a las Nubes is an extraordinary feat of engineering, and a good way to experience the dramatic landscape up to the puna.
Built to enable commerce over the Andes to Chile, the track, which runs 570 km from Salta to Socompa on the Chilean border, was the outstanding achievement of Richard Maury, an engineer from Pennsylvania. Work started in 1921 and took 20 years. The track starts in Salta at 1200 m above sea level, rising to 4200 m, up through the impossibly rocky terrain of the steep Quebrada del Toro gorge, with several switchbacks and 360-degree loops to allow diesel engines to gain height over a short distance with a gentler gradient. One thousand men worked with only the most basic tools through inhospitable conditions, detonating rock and carving away at steep mountainsides through howling winds and snow. Many died in the attempt. The destination of the tourist train (passengers no longer being allowed on the weekly cargo trains) is La Polvorilla viaduct, near San Antonio de los Cobres, a delicate bridge across a mighty gorge, spanning 224 m. At 63 m high, it feels like you’re travelling on air: both scary and exhilarating.
The tourist train is a comfortable ride, though a long day out. Leaving Salta at 0700 (cold and dark in winter) to the cheerful accompaniment of folclore singers on the platform, the train edges to the entrance of Quebrada de Toro, steep forested mountains tinged with pink as the sun rises, and a light breakfast is served. The landscape, dotted with farms and adobe houses, changes to arid red rock as you climb through the gorge, where giant cacti perch, past multi-coloured sculptural mountains to the staggeringly beautiful puna. The seven hours of the ascent are kept lively by chats from bilingual guides (English spoken; French and Portuguese too on request). Altitude sickness hits many people, and oxygen is on hand. At La Polvorilla viaduct, you can get out briefly to admire the construction and to buy locally made llama wool goods from the people of San Antonio. Don’t bother haggling: these shawls and hats are beautifully made and are these people’s only source of income. At San Antonio, the Argentine flag is raised to commemorate those who worked on the railway, and the national anthem is sung in a rather surreal ceremony.
The descent, however, is slightly tedious, despite the constant stream of entertainment from folclore singers and Andean bands. Consider returning by road instead to see the ruins at Santa Rosa de Tastil, one of Argentina's most important pre-Hispanic settlements. For more information, see www.trenalasnubes.com.ar.