“Notify when you leave and when you arrive”
Mayrit has already done the first. The second will be in more or less a month when all the pieces are already on Spanish soil. Mayrit is not the youngest son of a family. Mayrit has many fathers and mothers. Many.
Those necessary to give life to a 1,500 ton tunnel boring machine.
That tunnel boring machine that will directly expand line 11 of the Madrid Metro. A line that, until now, has been excavated with much more traditional means and that of course will take a huge leap forward in its future projection with this gigantic and enormous artifact.
What’s coming, what’s coming
Connecting Cuatro Vientos, southwest of the capital, with Valedebebas, northeast of it, Line 11 wants to become in one of those star connections in Madrid. Tracing a diagonal, the intention is to convert what is currently just seven stations into one of Madrid’s great corridors.
The qualitative and quantitative leap in the progress of the works will be made by Mayrit. This gigantic tunnel boring machine weighs 1,500 tons and is 98 meters long. It is expected that each day about 15 meters can be advanced on the land, key in a line that will have stations 33 meters below ground from Madrid.
My colleague Javier Márquez explained a few months ago that the transfer is not easy. The machine is built by Herrenknecht AGa German company that has assembled the entire gigantic puzzle of pieces, screws and components in its country. Once assembled, the machine is cut into pieces to be sent to our country. Of course, “it won’t be quick or easy,” as my partner explained.
Now we know that the powerful tunnel boring machine has already set out on its way to Spain. It comes by land and sea. And the bulk of its pieces will arrive in Santander by boat where they will board land transport to reach the capital. Another good package of these pieces will arrive at the port of Valencia, originating in Venice.

Map of the new Line 11
Once the pieces arrive, they must be transported to Carabanchel. There, next to Plaza Elpítica, this monster will drill into the ground at a rate of 500 meters per month to connect with Conde de Casal, about six kilometers from the point of origin. This stage is considered one of the most problematic and complex. Until now, the connection between Parque de Comillas (which will have a new station) and Plaza Elíptica is being done by hand.
However, the transfer and assembly is so delicate and complex that it will not be until March 2026 when everything is expected to be ready in the Madrid neighborhood to begin drilling the ground.
The system is so complex because the tunnel boring machine is not only responsible for excavating the earth and disposing of what is found there. While working advancing into the subsoil, an auger transports the excavated material with a conveyor belt. This material can be washed if it encounters mud but it can also affect the stability of the ground with injections of bentonite, water or foam. All while sensors control the pressure the machine experiences to control how fast it can work.
If everything happens according to the planned deadlines, the last piece from Mayrit should arrive in December and, as we said, it is not expected to come into operation until March 2026. For now, it’s time to pull the shovel and pneumatic hammer.
Photo | Madrid Metro

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