The mining railway from Sierra Menera to Sagunto Historical milestone · Ojos Negros, Jiloca, Teruel Between 1904 and 1907 a narrow-gauge railway of two hundred and four kilometres was built to carry the mineral to the port of Sagunto. It operated until 1973 and its course today supports the longest greenway in Spain. 1904-1907 Photo: Pacopac (CC BY-SA 3.0) What to see and do in Ojos Negros