This encompasses the construction of the railway platform and standard gauge track connection between Atocha and Chamartín stations. To do this, a tunnel has been constructed with an excavated diameter of 11,495 m and a length of 7,300 m. The tunnel runs from south-north, from Atocha station, along c/ Alfonso XII, c/ Serrano Street and the “El Viso” urban development up to Chamartín.
The landscape is basically urban, passing under the Puerta de Alcalá (a monument of high architectural value ) at a depth of 31 m.
Adopted solution: Double track tunnel with an interior diameter of 10.40 m with emergency exits every 775 m, which will also be used for pumping and ventilation in the tunnel.