In the Sierra Greenway, there are thirty tunnels. Of these, the longest one is the Castle tunnel, with 990 metres, near Coripe station. Those that exceed 150 metres or which have a curved path, are illuminated, some with conventional system and others with solar systems. You can also enjoy the darkness in the unlit ones … it is a very mysterious feeling. In summer, coolness in the shade of a tunnel is appreciated, a fact that goats sometimes take advantage of. At sunset, you may be able to see some bats emerging from their shelter inside the vaults.
For its construction the opening and indoor progress in the interior of the tunnels was done by hand, using the curing of curls and wooden beams, as in mining, to support the walls and the ceiling. The formwork of wooden frames formed the first concrete sample of the time, a leading construction technique in Spain in the 1920s . The mouths are finished with quarry stones and offer the appearance of a bridge eye in which the ‘key stone’ is located in a strategic place.
This majestic work built with the stoic work of the people of the place, who changed the plow for work tools, is still present as a silent witness of past times.
Shortly before the tunnels were restored, the picture was very different from the current one. Some were used for the cultivation of mushrooms, like the name of some of them show, or they served as sheepfolds. Others did not go on to live such fortunate uses and suffered erosion, collapse or flood by leaks.