The Mayrit Tunnel Boring Machine: Progress Under Madrid
It commenced its journey on March 26, and in little more than a month, the Mayrit tunnel boring machine (TBM) has successfully drilled the first 200 meters beneath the streets of Madrid. This ambitious project aims to complete over 5,200 meters of tunnel by the end of 2027, paving the way for the transformation of Metro Line 11.
Initial Phase: Adjustments and Early Progress
During the initial month, the tunnel boring machine operated at a slower pace due to necessary adjustments. According to the Department of Transport and Infrastructure of the Community of Madrid, these first 200 meters were completed while the TBM was still in its calibration stage. Now that the adjustments are complete, the Mayrit is set to hit a cruising speed of 400 to 500 meters per month—about 15 meters daily.
What Happens Underground?
The process is not as simple as just digging. As the cutting wheel of Mayrit, equipped with 54 discs, 172 picks, and 24 battens, pulverizes the earth, it simultaneously installs concrete segments that form the tunnel’s final structure. Additionally, it extracts around 3,500 tons of earth daily through conveyor belts that transport the material to the surface, where about 150 trucks then carry it to designated landfills and disused mining sites.
Complex Assembly Process
Building a 98-meter-long, 1,500-ton machine deep below the surface is no small feat. Manufactured in Schwana, Germany, the Mayrit traveled 2,000 kilometers by land and sea to reach Madrid. Its assembly was a meticulous process that took 70 workers three months to complete, all within the preparations for the future Comillas station.
Operational Schedule and Maintenance Stops
Mayrit operates tirelessly, 24 hours a day, seven days a week, but it has scheduled stops for inspections. The first of these will occur once it reaches the upcoming Madrid Río station, approximately 1,114 meters from Comillas. There, it will undergo a technical assessment for up to two weeks. Future stops will happen at Palos de la Frontera, Atocha, and Conde de Casal, with potential mid-journey stops for necessary repairs about every 1,000 meters.
Projected Timelines
The total distance for the Mayrit’s excavation journey is 5,227 meters from Comillas to Conde de Casal, where a new interchange will be constructed. Miguel Núñez, the General Director of Collective Transport Infrastructure for the Community of Madrid, estimates that the tunneling will take approximately 13 to 14 months to complete. Consequently, if drilling commenced at the end of March, we can expect completion around May or June 2027, with the public opening delayed for installation and testing.
Substantial Material Requirements
To finish this section, significant resources are necessary, including 32,000 tons of steel, 210,000 cubic meters of concrete, and over 25,000 segments. Production of these materials commenced in September 2025 at a factory specifically established for the project. The overall completion of these works is over 50%, with investments in the initial phase exceeding 740 million euros.
A Vision for the Future: Line 11 Expansion
This project is merely the tip of the iceberg. The future Metro Line 11 will span 33.5 kilometers from Cuatro Vientos to Valdebebas, featuring 20 stations designed to enhance connectivity to vital locations such as Atocha, the airport, and the future Formula 1 circuit in Ifema. The complete journey will take just over an hour, with total investments for the entire project projected to surpass 2.5 billion euros, completed in four phases by 2031.