Madrid’s ambitious transformation of Metro Line 11 has reached a decisive new phase, with the ACCIONA–Dragados–Rover consortium accelerating excavation on the 6.9‑kilometre Plaza Elíptica–Conde de Casal section. The project—now more than 50% complete—forms the backbone of the future 33.5‑kilometre “Diagonal Line,” a cross‑city axis designed to reshape mobility across the Spanish capital.
TBM Mayrit: A High‑Performance Herrenknecht Giant
In late March 2026, the consortium launched full‑scale tunnelling using Mayrit, the Herrenknecht‑built TBM engineered specifically for Madrid’s geology. The machine’s specifications underline the scale of the undertaking:
- Length: 98 m
- Weight: 1,500 t
- Outer diameter: 9.4 m
- Daily advance rate: Up to 15 m/day
- Segmental lining: 8,340 mm inner diameter, 320 mm thickness
Mayrit will excavate approximately 90% of the tunnel between Comillas and Conde de Casal—around 5.6 km of the total alignment—following an initial 679 m excavated using the traditional Madrid method.
A Complex Underground Corridor: Stations, Shafts, and Safety Infrastructure
The Plaza Elíptica–Conde de Casal extension incorporates a dense package of underground works:
Five Stations
- New builds: Comillas, Madrid Río
- Refurbished interchanges: Palos de la Frontera, Atocha, Conde de Casal
As of early 2026, station progress varies significantly, with Comillas and Madrid Río surpassing 60% completion, while Atocha and Conde de Casal continue to advance through more complex interchange works.
Auxiliary Structures
- Seven emergency exits
- Five ventilation shafts
These structures are essential for safety, ventilation, and operational resilience across the new corridor.
Project Timeline and Investment
- Initial works: Began November 2022
- Current status: Over 50% complete
- Scheduled completion: End of 2027
- Contract value: €500–€558 million for this section
- Additional equipment tender: €123.1 million for lifts, escalators, fire protection, and operational systems across the new stations
The equipment package includes 29 elevators and 60 escalators, ensuring full accessibility in line with Madrid Metro standards.
Environmental Commitments: A Greener Metro Expansion
Responding to community concerns—particularly in Madrid Río and Comillas—the project has incorporated significant environmental mitigation measures:
- Tree felling reduced by 50%
- 14,000 new trees to be planted in municipal areas
- Route adjustments made following neighbourhood consultations and protests in 2023
The extension is also partially financed through the EU Recovery Fund, supporting green transition and urban cohesion objectives.
The Future “Diagonal Line”: A New Backbone for Madrid
The current works represent the first major phase of Madrid’s plan to convert Line 11 into a 33.5‑kilometre diagonal corridor stretching from Cuatro Vientos in the southwest to Valdebebas in the northeast.
Network Integration
Once complete, the line will connect:
- 11 of Madrid’s 12 metro lines
- Seven major interchanges, including Atocha and Barajas Airport (T4)
- Key destinations such as IFEMA, Hospital Isabel Zendal, and the Valdebebas development zone
Strategic Impact
- Decongesting Line 6 (Circular)—currently one of the network’s busiest
- Providing a fast south–north alternative without passing through the historic centre
- Improving cross‑city travel times and reducing reliance on radial routes
The northern extension—approved in 2026—will add six new stations between Mar de Cristal and Valdebebas Norte, with construction expected to begin in 2027.
A High‑Precision, High‑Ambition Project
The breakthrough achieved between Plaza Elíptica and Comillas in early 2026 demonstrated the precision of the engineering and topographical control underpinning the project.
With Mayrit now driving the main excavation and station construction progressing steadily, the Line 11 extension is on track to become one of Madrid’s most transformative mobility investments in decades.
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