A train carrying sulfuric acid with 5 Locomotives of the Chilean railway company FCAB, crosses, through a large horseshoe, the railway line known as "Cumbrepass" railroad connection between large copper mining and seaport of Mejillones, in the Atacama desert, second region of Chile. The Cumbrepass characterized the difficulty of their route, it must reach a great height in a few kilometers for which the train travels through multiple curves and steep inclines of ascent and descent.