The Mayoral Viaduct is a dual-track structure located between Chainage 2+439.492 and 3+093.089 on the Barcelona-bound track.

The viaduct features a continuous deck with 19 spans (29 m + 17 × 35 m + 29 m), totaling 653 m between the support axes at the abutments. The elevated section over the existing Madrid–Barcelona High-Speed Rail Line (LAV) is a highly skewed crossing, resolved with a portal-frame pier that splits the passage into two spans of approximately 35 meters each, allowing the foundations to be built without affecting the platform.

Most of the viaduct’s spans use a single-cell post-tensioned prestressed concrete box girder, except for spans 13 and 14—under which the existing Madrid-Barcelona LAV platform passes—where a composite deck (precast beams + in-situ slab) was chosen for easier construction over the operational track.

As part of FHECOR’s work on the Modified Project, the construction procedure for the deck was adapted: from abutment E1 to span 11 (Phases 1 to 11), an underslung launching gantry was used, with span-by-span concreting and tensioning from the phase front.