Through the Mauritanian desert, about 10 kilometers east of the Ben Amira monolith, a two to 2.5 kilometer long loaded iron ore train approaches from Zouérate/F'derîk to the port of Nouadhibou around noon. Above the “mineralier”, as the loaded trains are called here, traveling at around 50 km/h, lies a cloud of diesel exhaust fumes, the finest desert sand and dust from the iron ore. At the head of the train are around 10,000 HP, the locomotives SDL40-2 CC # 118, SD70ACS CC # 127 and the SDL40-2 CC # 113 in multiple control. In the distance, at the rear of the train, two oil tank cars, container cars and 8 empty water tank cars can be seen. The trains on the 650-kilometre line are among the longest and heaviest regularly running trains in the world, with over 200 carriages and weighing over 20,000 tons.