The freight train returns to FCALP / Ferrocarril Arica a La Paz: We see a fraction of the train (1/4 of the train) going up an area of horseshoe curves near Pampa Ossa, advancing through the most complex section of the trip, which is between Central and Puquios. Pampa Ossa is an intermediate point between Central and Puquios, 43 km (27 miles) of hard travel with slopes of 6% to be able to pass the narrow and steep ravines "Quebrada de Quiroz" and "Quebrada Honda". In this part of the trip, the railway ascends 2,247 meters (7,372 feet) in altitude (from 1,481 meters above sea level - 4,859 feet - to 3,728 meters above sea level - 12,231 feet).