Basque regional train operator Euskotren has opened an underground section of line between Altza and Galtzaraborda, east of San Sebastian, on July 18, according to railwaygazette.com.

The bypass eliminates a bottleneck on the Topo network by avoiding the need for trains to reverse at Altza, which is now a through station.

The 2.1 km double-track metre-gauge section opened to passengers a day after an inauguration ceremony.

With the new infrastructure in service, suburban services between San Sebastian and Pasaia have been doubled to run every 7.5 minutes on weekdays and every 15 minutes at weekends. This increases the number of daily Euskotren train movements from 136 to 274.

Underground station

The civil works contract awarded to a consortium of Comsa, Nortúnel, Campezo and Azvi in 2021 was worth €64.1 million and included the excavation of 2.1 km of tunnel using the New Austrian Tunnelling Method.

Signalling, electrification, telecoms and other railway systems were procured under separate contracts; Comsa undertook electrical and mechanical works, including electrification.

A replacement underground station in Pasai Antxo was designed by Norwegian studio Snøhetta. To minimise disruption above ground, it was built using a top-down excavation method, with the upper roof slab laid first and then excavations undertaken underneath.

The former surface railway alignment, including a viaduct dating from 1912, is to be dismantled, removing an historic urban barrier and freeing up 2,800 m² of land.

In addition to this bypass focused on passenger traffic, Basque rail infrastructure manager ETS is also working to reconnect the port of Pasaia to the metre-gauge railway network to shift freight from road to rail.

Fleet expansion

The service increase is being supported by new rolling stock. In July 2023 Euskotren awarded CAF a €53.6 million contract to supply five four-car Series 980 EMUs for the future Bilbao metro Line 5, before it then decided to deploy them first on the Topo network. The fleet will provide the additional capacity required by the Altza – Galtzaraborda line and the future San Sebastian city centre tunnel.

The first unit was delivered in March 2026. Each set has a capacity of around 400 passengers and is equipped with an accessible toilet. Once all trains arrive, Euskotren will operate a fleet of 67 EMUs.