The Ministry for Development has awarded the building of the high speed rail track and tunnel connecting the stations of Atocha and Chamartín to FCC in a temporary joint venture with other companies. The budget is €206 million with an undertaking schedule of 32 months.

This section of new route has double international gauge track and is 7.33 km long, of which 6.9 km are underground. It will start in Méndez Álvaro Street, followed by Alfonso XII street and passing under Serrano Street to the República Argentina Square where it will then follow current urban planning regulations with a new track between Francisco Suárez and Mateo Inurria streets until it reaches the southern head of Chamartín station.

The project also includes building of the track and remodelling the sidings at the southern head of Chamartín station. Most of the route, approximately 6 km, will be built with an EPB tunnel boring machine with an excavation diameter of 11.4 m at a depth of some 40 m so that the building work will not affect the life of the city too much.