The itineraries that form part of the Montes de Hierro Greenway Nature Trail (Burdinmendi in Basque) cover part of the route of two railway lines once used by the mining industry: Castro-Urdiales - Traslaviña and Sestao - Galdames.
In use since the 19th century, they ceased to operate in the 1960s and 1970s. After years of neglect, in 2006 a restoration began to prepare them for recreational use. The following sections of the Nature Trail Network are now open:
The main purpose of both railway lines was to carry iron ore from the mines in the Las Encartaciones valleys (Enkarterriak) to the coastal loading docks (Castro-Urdiales and Sestao), although they would also be used to improve passenger transport in the area.
The difficult orography in these territories made it necessary to build numerous tunnels and bridges, many of which have been opened for the Nature Trail. This, along with the beauty of its valleys, makes this itinerary an especially recommendable option for exploring this district in the west of the Basque Country.
To round out your knowledge of the area’s mining industry, it is possible to complete this itinerary with the Castro-Traslaviña Greenway (Cantabria), to use the network of cycle paths that lead off from the Nature Trail and reach the River Nervión or to continue along the Greenway that runs along the route of the “Covarón railway” as far as the ruins of the El Castillo loading dock at Muskiz.