The world-famous iron ore train begins its outbound journey from the mines at Zouerate and ends at the long quay just outside Nouadhibou, where the ore is loaded onto ships. The train itself is a legendary travel experience: free passage on the open wagons for the brave, a single passenger carriage at the back for those who prefer not to inhale ferrous dust.
It leaves Nouadhibou in the late afternoon and arrives in Zouerate the next morning, twelve to sixteen hours later. Take warm clothes, water, dust goggles and a head torch. Mauritanians do this routinely — you will not be alone — but it is hard travel and best treated as an adventure.