The €232m project was funded entirely by the Basque government and included the construction of an underground station in the town centre. It will allow the closure of the original line, which cut through the centre of the town with seven level crossings.

The tunnel opened 130 years to the day after the first train from Bilbao arrived in Durango, and is a key part of the upgrading of the Bilbao – San Sebastian line, which includes 15km of track-doubling, elimination of 27 level crossings, and construction of new stations at Euba, Durango and Traña.