Nowadays, the rail trail runs between Arlanzón and Monterrubio. The possibility of extending the route from Arlanzón to the archaeological sites of the Sierra de Atapuerca, which were discovered by the mining railway works, had been considered.
History
In 1896 the British company "The SierraCompany Limited" got permission from the Spanish government to build a narrow gauge railway to transport iron from the mines of the Sierra de la Demanda to Burgos, and once there to the Basquesteel mills through the Burgos-Bilbao railway line. In 1901 the line was opened. Shortly after, a license to transport passengers was granted, but the company only performed freight services. Nevertheless, the line remained loss-making due to high operating costs to Bilbao, and was closed in 1910. In 1947 the line was dismantled and fell into disrepair. Earlier this century, the idea of converting part of the railway line into a greenway for walkers and cyclists came into reality, being finally opened in 2004.
Description
Throughout the path's 54 km a great variety of flora and fauna can be found including birds of prey, squirrels, foxes, deer and wild boar. Leaving Arlanzón, the route runs between stands of pine and ash, until it enters a dense forest of oakon the way to the Arlanzón reservoir. At 10 km is the first tunnel, which is closed as the ceiling has fallen. A parallel steep track avoids the obstacle. A few km later we will reach the dam, where there are several rest areas. At 23 km is Pineda de la Sierra, declared a historic-artistic complex with mountain-style architecture houses and a romanesque church with portico. Until recently, the greenway stopped here, and trail users had to go by the roadfor a while, as the trail had been occupied by an individual who claimed possession. In 2009, the Supreme Court found in favour of the Pineda de la Sierra town hall in their dispute with the landholder. The route continues parallel to the River Arlanzón, and sandwiched between the mounts Mencilla and San Millán. At 31 km the Manquillo tunnel appears, through which the train avoided the mountain passof the same name. Nowadays, the tunnel is closed because of its poor maintenance condition, and the route follows a very steep hill to avoid the pass. Once over the summit, the way descends between closed curves and beech forests. At 40 km is the last tunnel on the way, and the only one open. From here, a dirt track connects the greenway with Riocavado de la Sierra. At 44 km is Barbadillo de Herreros, a village with a mining past, where we can visit a furnace and other remnants of the old ironworks. The greenway follows a zig-zag route by a pyrenean oak forest up to the former village of Bezares, and quickly leads to 52 km, where there is a recreation area with a hut, water source and grills. By continuing a couple of miles further on paved trail Monterrubio de la Demanda is reached at the end of the route.
