Tren a las Nubes: the guide I wish I'd had before climbing to 4,220 meters

At 4,220 meters of altitude, with the train's steam mixing into the clouds over a 224-meter viaduct: that's why no one forgets the Tren a las Nubes. But before you buy the ticket, there's a handful of details that decide whether your experience will be unforgettable or just another postcard photo. I learned this the hard way, and I've laid it all out here.

The legend behind the train

The Tren a las Nubes is one of the highest rail routes in the world and the star attraction of northern Argentina. Construction began in 1921 and took 27 years of work under extreme conditions, connecting Argentina and Chile across the Andes. The name was born in the 1960s, when the train's steam started mixing with the clouds right at the highest point of the route: the Viaducto La Polvorilla, 224 meters long and 63 meters high. That's where the trip becomes legend, and where you'll get the classic photo, the train curving over the viaduct surrounded by the Andes.

First surprise: the train no longer leaves from Salta

This changes your whole plan. Today boarding happens in San Antonio de los Cobres, at 3,775 meters of altitude, and you choose between two experiences:

• Full package: bus departing from Salta, a rural breakfast in El Alfarcito, and boarding the train in San Antonio de los Cobres.
• Just the train leg: ideal if you're already in San Antonio de los Cobres, buying only the round trip to the viaduct.

Both go on sale on the official Tren a las Nubes website. The right choice just depends on where you'll be.

The detail that changes the whole view: your seat

Buy directly on the official website to choose your car and seat, and do it early, because spots sell out fast. Now the golden tip: a left-side seat on the way there (look for numbers 15 or 16), because that's where you'll see the canyon and the viaduct in all their glory.

I bought my ticket without knowing any of this, got seat 9 on the wrong side, and spent the first part of the trip looking at the wrong side of the mountain. I switched to 15 as soon as I could, and the difference was out of this world.

Keep this in mind: everyone switches sides on the way back, so whoever sat on the left returns on the right. It's the train company's own policy, to make sure everyone gets to enjoy the view from both sides.

4,220 meters show no mercy: how to prepare

This is likely the highest point you'll ever have been in your life, and your body feels it. Bring coca candy, leaves, or tea: it's the local trick to ease altitude sickness. Eat light before the trip, avoiding dairy and fat, and hydrate more than usual. For the cold, which is biting at the top, bring a beanie, gloves, and a scarf. And relax: there's a doctor on board and oxygen available if you need it.

The dining car: a strategy switch

Save your meal for the way back. On the way there, the scenery and the anticipation take over; on the way back, the altitude catches up with you in the form of sleepiness, and eating there, with the windows open and no glass reflection, is the right move for photos and for enjoying the moment.

Before you get off the train

Stop by the souvenir car and stamp your passport: it's the kind of memory worth more than any fridge magnet. And at the curve of the viaduct, camera in hand: that's where the photo you'll post, and rewatch, for years is born.

Heads up: some countries take issue with this stamp and may treat it as tampering with your passport, refusing to accept the document. I chose to get it stamped, knowing the risks.

If Salta is on your list, the Tren a las Nubes needs to be too. The right seat, a jacket in your bag, coca candy in your pocket, and a spot booked for breakfast in El Alfarcito. The rest, the train and the Andes take care of for you.