The stretch of the new Basque railway network runs mostly through a tunnel in Beasain and belongs to the Ordizia-Itsasondo stretch.

More than the 80% of the route goes underground, whereas the 15% corresponds to viaducts and only 300 metres will be constructed outdoors. In total, the stretch through Beasain consists of 5 tunnels and 4 viaducts.

The stretch of the Basque Y enters the borough of Beasain through the Solozarreta tunnel (750 metres), and next crosses the Zabalondo stream through a 224-metre-long viaduct. Afterwards, the stretch of the Basque Y enters the tunnel of Arriarán (467 metres long) and it goes through Vega de Ítola through a viaduct composed of 9 openings and with a length of 382 metres.

The next stretches of the route are in the tunnels of Ítola and Loina (of 201 and 347 metres each), which are separated by an 80-metre-long outdoor stretch.

The stretch goes outdoors again to cross the Usurbe stream through a 52-metre-long viaduct. Finally, the tunnel of Beasain (1995 metres) will lead to the end of the borough, where the Mariaras stream flows and there is a 111-metre-long viaduct.

Furthermore, a new station will be constructed in this stretch of the New Basque Railway Network, specifically in the borough of Ezkio-Itsaso, 10 kilometres far away from Beasain. This new station for passengers and goods will provide service to "passengers from the regions of Alto Deba und Goierri" and serve "as a exchange point for goods".

The stretch of the Basque Y in Beasain will have the latest innovations regarding security and respect for the environment, and the impact caused by it will not be bigger than that produced by any other kind of infrastructure.

Moreover, the infrastructure will be almost "invisible", since, besides being set up in tunnels, the stretch will be away from the town and will only approach at the way out to Ordizia, near the CAF premises.

The Department of Transport and Public Works of the Basque Government is responsible for carrying out the project and the awarding and tendering processes to be executed in this borough.