This new bypass will allow for 7.5-minute frequencies at all stations between Amara and Pasaia. Previously, this frequency was only available up to Herrera, with waiting times of 15 minutes in Altza and Pasaia.

Details of the project were presented at the underground station beneath Gure Zumardia square in Pasai Antxo. With the new bypass in operation, Altza station will no longer be a dead end, as it will connect with the new underground Pasai Antxo station, set to open soon. Later, the old terminal will be dismantled, and the viaduct crossing Pasai Antxo will be removed.

According to the construction management, work on the slab track between Altza and Galtzaraborda has been completed within the new station's concourse. Only the section closest to Galtzaraborda, the ballast track, remains. The terminal is almost finished, and the civil works for the track will conclude in June, with only the entrance coralline, metal carpentry finishes, ventilation area partitions, and technical rooms left to complete.

Regarding installations, the under-platform and emergency ventilations at the ends of the station are being assembled. Signaling work is also progressing, and the installation of rigid catenary bars has begun. In Galtzaraborda, progress has been made on wall foundations, and work is underway on both the end of the walls and the slab of the slab-ballast transition, as well as the ballast track between the tunnel exit and the station itself.