The Adif line serving Renfe-Cercanías runs underground at Reketa (Barakaldo) thanks to the box built in the section between Avenida de Altos Hornos (near the Desierto-Barakaldo station) and Rontegi bridge. The structure of this false tunnel is formed by reinforced concrete support pieces on which prefabricated pre-stressed concrete beams were placed. One of the aims of this action is to facilitate the development of the Reketa area towards the estuary with the aim of urbanising land with an approximate surface area of 40,000 square metres where, in accordance with the General Plan, urban equipment and elements to revitalise the area will be implemented.
- Length of covering: 475 linear metres of railway track between Avenida de Altos Hornos and Rontegi Bridge
- Box dimensions: 16.5 metres wide and 6.5 metres high
- Annex building that serves as an emergency exit and houses the ventilation system and railway and safety installations