The Tren a las Nubes (English: Train to the Clouds) is a tourist train service in Salta Province, Argentina. The service runs along the eastern part of the Salta–Antofagasta railway line of the Belgrano Railway (also known as the "C-14" line) that connects the Argentine Northwest with the Chilean border in the Andes mountain range, over 4,220 metres (13,850 ft) above mean sea level, the fifth highest railway in the world. Originally built for economic and social reasons, it is now primarily of interest to tourists as a heritage railway, though cheaper tickets are also available for locals to use the train as transport.