High-Speed Lines

Atocha - Chamartín high-speed tunnel

Banco Europeo de Inversiones

Logo of The European Investment Bank (EIB)

The European Investment Bank (EIB) collaborates in the funding of this project.

Project benefits

The U.I.C. gauge railway connection that will connect the stations of Madrid-Puerta de Atocha and Madri-Chamartín will constitute an essential infrastructure for the development of a structured international gauge network in Spain, for it will enable the interconnection of all the high-speed lines that cross Madrid, favouring the interoperability of high-speed trains.

The tunnel will improve the operation model of both stations in Madrid, as they will go from having a terminal configuration to being transit stations.

Its going into service will be made to coincide with the quadruplication of the tracks between Atocha and Torrejón de Velasco. At that time, all Southern/Eastern high-speed lines will be connected to those in the North, allowing direct connections to be made in UIC standard gauge through this tunnel.

Once these important works have been completed and the Puerta de Atocha and Chamartín stations have been restructured, the tunnel will give the passengers the chance to choose from Chamartín or Atocha as their departure or arrival high-speed station in the capital.

Madrid will enjoy the privilege of having its high-speed stations connected, something that other important European cities have not yet achieved.

Image of the tunnel’s route (PDF)

Tunnel Characteristics

The new double track connection via Atocha-Chamartín is 7,313 metres long, with international gauge double plate track  Most of the excavation will be carried out with the tunnel boring machine, except for the first and last few metres, which will be carried out by other means.

The section, runs from Chamartín towards República Argentina square. From here it continues under the axis formed by Serrano and Alfonso XII streets. Finally it passes under the botanic garden and the Emperador Carlos V roundabout, reaching Puerta de Atocha.


Its route crosses eight Metro lines, passes under the suburban train tunnels of Recoletos and Sol, in Atocha, and in the Chamartín area it will run parallel to the Recoletos tunnel for about 400 metres.


The project includes the remodelling of the shunting yard of Chamartín’s southern section. The tunnel boring machine has been set up in this area, and it will be from here that the tunnel excavation will begin.

The tunnel will have eight emergency exits, five of which have direct access to the surface and the other three, in Serrano street, will communicate with the outside through underground car parks which are currently being built. The maximum distance between these exits will be one thousand metres. In addition, the tunnel will have three ventilation shafts and five pumping wells.

Tunnel Boring Machine

For its construction, most of this infrastructure will be executed with an EPB (Earth Pressure Balance) type tunnel boring machine made by the German manufacturer Herrenknecht, with an excavation diameter of 11.5 m, and an inner diameter of 10.4 m. The total weight of the tunnel boting machine is 2,200 t, with a length of 125.6 m.

The cutting wheel is powered by eighteen 350 kW engines, with a total installed power capacity of 6,300 kW.

The coating will be carried out with precast reinforced concrete ring segments 1.8 metres wide and 36 cm thick, resulting in an open inner diameter of 10.40 m.

Tunnel Boring Machine


Prior to the construction of the tunnel, detailed inspections have been carried out on the buildings located on both sides of the corridor through which the tunnel will run to obtain as much information as possible and to ensure that the execution of the construction work will not affect the surrounding buildings. More than 470 buildings have been inspected, and out of these buildings more than 1000 homes have been inspected.

In addition, periodical controls are being carried out thanks to the installation of instruments and subsequent auscultation of the ground both on the surface and below it throughout the tunnel’s route. The underground infrastructures near the tunnel will also be instrumented (underground car parks and Metro and suburban train tunnels), as well as all the buildings within the tunnel’s sphere of influence.

Environmental Protection

From an environmental point of view, the tunnel represents a small effect. The most important aspects are:

  • Archaeo-paleontological Works
  • Measurements and auscultation. Periodic dust, noise and vibration measurements.
  • Protection and transplantation of trees, in collaboration with the Green Heritage of the Madrid City Council
  • Lime waste processing and its transport to authorized dumps.

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