
El Polvorilla viaduct, the train’s highest point (4,200 meters above sea level)
I imagine Richard Maury, the American engineer who built the Cloud Train, must have taken a very deep breath when he first looked up at the route that snakes into the mountains. The finished result climbs to 4,220 mts (13,841 ft) and traverses: 29 bridges, 13 viaducts, 21 tunnels, 2 spirals and 2 zigzags. It is one of world’s most extraordinary engineering achievements – especially as on top of all the difficulties Maury had to deal with a military coup in Argentina.
The railway was finally inaugurated in 1948, fifty-nine years from when the project was first proposed. Alas, soon after the inauguration the first major highway was built over the Andes making the train practically obsolete and it didn’t take long before it fell into disrepair. However, it now has had new life breathed into it as one of the premier tourist attractions in Salta and the northwest.
The route starts in the city of Salta and the lush Lerma valley before steadily climbing up into the Yungas forests.

Crossing the Rosario river in the Yungas (cloud forest)
It then arrives at the Puna, a vast mountain plateau that stretches across parts of Chile, Argentina, Bolivia and Peru. Here it makes a stop in the dusty town of San Antonio de los Cobres; the station of which appears to be where they filmed the first scene of Sergio Leon’s ‘Once upon a time in the west’.

The dusty one horse town of San Antonio de los Cobres
The train then makes one more stop, at the famous Polvorilla viaduct, before heading back down to the lowlands.