This route travels 10 kilometres along the ravines of the southern Central Massif where the paths created for the extreme dramatic construction of the second railway line which would join Zamora-Orense. In 1927, Primo de Rivera’s government decided to build new railway lines, thus the Zamora-Ourense project was revived, which also contemplated going from Ourense to Santiago and A Coruña. At the end of the Civil War, the new regime takes over the works, which are restarted and from then are also done by political prisoners. It was this second section where line construction was harder and more expensive due to the terrain, since over 80 tunnels had to be drilled. The drilling and earth works were done manually in very precarious human and technical conditions in exchange for a minimum wage.
This work meant long years of works with thousands of people who fell ill prematurely due to the so called "road disease" or silicosis, due to which many tunnel workers died. There were also many industrial accidents because the works lacked minimum safety measures, destroying the lives of many. Observe how spectacular the Armada ravine is, from where you can calibrate the magnitude of the work executed.