The Maria Elena – Tocopilla line was the last operating nitrate railway, built to transport caliche and nitrate from the mines farther inland to the processing plants and port at Tocopilla. All trains had to change their locomotives at the station of Barriles. Diesel was used for the line from the mines to Barriles, whereas the steep line down the coast range to Tocopilla was electrified. The service was permanently discontinued in 2015, after 125 years of operation.