It is a viaduct over the Esla River on the Ricobayo reservoir in Zamora (Spain). The structure, 368 meters long, forms part of the 20.3 kilometer Hiniesta-Perilla de Castro sub-section, which was also awarded to the company, and the Zamora-Lubián section of the Madrid-Galicia high-speed line.
It consists of spans measuring 70, 93, 50 and 155 meters, the largest of which is also the longest high-speed railway span in Europe, and one of the longest in the world, built using the progressive segment system, with two pairs of formwork carriages. In addition to the construction of the viaduct, the works also included the construction seven overpasses, ten underpasses, two pergolas over the N-630, and two wildlife crossings.
The infrastructure is located on the Ricobayo reservoir, which posed a number of challenges, including the designing and planning of the structure and the auxiliary resources required for the execution to allow continuous construction over time, regardless of the water level in the reservoir. This required the viaduct to be redesigned to adjust the distribution of the spans to the geographical conditions and the statistical water level of the reservoir that guarantees the preservation of a medieval mill that is protected as historical heritage by the Castile and Leon Regional Government (Spain), located in the immediate vicinity of the works.