It started on March 26 and in just over a month it has already left behind the first 200 meters of tunnel under the capital’s subsoil. The Mayrit tunnel boring machine advances towards Madrid Río with the objective of completing more than 5,200 meters of gallery before the end of 2027. And all to prepare the ground for the transformation of Metro L11.
full throttle. The first month was slower than usual because the TBM was still in the adjustment phase. So has explained it the Department of Transport and Infrastructure of the Community of Madrid. And those first 200 meters have been drilled with the machine still running. However, from now on, Mayrit will reach its cruising speed: between 400 and 500 meters per month, which is equivalent to about 15 meters per day.
What exactly is he doing underground. In addition to excavating (logically), as its cutting wheel, equipped with 54 discs, 172 picks and 24 battens, crushes the ground, the machine also places rings of concrete segments that form the final structure of the tunnel. At the same time, extracts about 3,500 tons of earth per day through conveyor belts that extend to the surface, where a hundred and a half trucks are responsible for transporting this material to landfills and disused mining operations.
Transfer to the capital. Assembling a 98-meter-long, 1,500-ton machine at a depth of 27 meters is not a simple process. Mayrit was manufactured for 20 months in the German city of Schwana and traveled 2,000 kilometers by land and sea until reaching Madrid. Once here, it took 70 workers three months to assemble it piece by piece inside the future Comillas station.
When does it stop and why? Mayrit works tirelessly 24 hours a day, seven days a week, in continuous shifts. But has scheduled stops. The first will be when it arrives at the future Madrid Río station, 1,114 meters from Comillas. There it will undergo a technical review of up to two weeks. Then he will repeat the process in Palos de la Frontera, Atocha and, finally, Conde de Casal. It can also stop at any intermediate point if any part needs replacement, which is scheduled approximately every 1,000 meters.
The final destination and when it will arrive. The total route entrusted to Mayrit is 5,227 meters between Comillas and Conde de Casal, where the future interchange is located. The general director of Collective Transport Infrastructure of the Community of Madrid, Miguel Núñez, estimated In statements collected by 20 Minutes that the complete excavation will take between 13 and 14 months.
With startup at the end of March, that puts the end of drilling around May or June 2027. Opening to the public will take a few more months, once installations, equipment and testing are completed.
The work behind the tunnel boring machine. To complete this section 32,000 tons of steel will be needed210,000 cubic meters of concrete and more than 25,000 segments, whose production began in September 2025 in a factory created expressly for this project. The overall progress of the works already exceeds 50%, according to the City Council, and the investment in this phase amounts to more than 740 million euros.
The biggest project behind it. All of this is just a part of something much bigger. The future Line 11 will travel 33.5 kilometers from end to end of Madrid, from Cuatro Vientos to Valdebebas, with 20 stations that will connect points such as Atocha, the airport, Zendal Hospital or the future Formula 1 circuit in Ifema. The complete route can be done in one hour and six minutes. The total investment exceeds 2.5 billion euros and the works will be carried out in four phases until 2031.
Cover image | Community of Madrid
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