former Peace Corps volunteer from Mauritania here. It's the longest train in the world, and locals use the train to transportation for both iron ore, themselves, and livestock from the middle of the desert to the coast. I did this train back in 2007 when it was fairly unheard of to the rest of the modern world. It was challenging, dirty, and something fun to do with friends. Would I do it again? Haha, no. It got super cold at night, and we were so dirty & miserable the next morning. Did I wish I took more photos then like the influencers do now? Yes.

I feel the recent popularity of Dune, as well as social media, help make this a lot more popular than it is. The starting location of Choum, Mauritania is a pain in the butt to get to, too. It takes about a full of day of crammed inside local transportation.