Underground Works

Since its first metro project in Spain in 1944 and its international expansion in 1965, DRAGADOS has delivered more than 550 underground projects across twenty countries on five continents, executing over 900 miles of tunnels, galleries, and shafts, and establishing itself as a global benchmark in underground construction.

This experience spans all types of infrastructure—roads, railways, metro systems, hydraulic works and mining—as well as the application of a wide range of construction methods, from TBM tunneling (EPB, Double Shield, Gripper, and microtunneling) to drill and blast, mechanical excavation, and other specialized techniques.

The diversity of methods employed and the wide range of geological environments in which the company has operated reflect DRAGADOS’ ability to select and adapt the most efficient construction solution for each project, ensuring safety, innovation, and technical excellence.

Miles of road tunnels

Miles of railway tunnels

Miles of subway tunnels

Miles of water tunnels

Miles of mine & service tunnels

Total miles

Miles of road tunnels

Miles of railway tunnels

Miles of subway tunnels

Miles of water tunnels

Miles of mine & service tunnels

Total miles

Our experience

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Underground works

Madrid Calle 30

Madrid, Spain

The redevelopment of the Southern section of Madrid's inner ring road, known as Calle 30, included the construction of an underground bypass that required the road to be buried using a twin-tube tunnel design, with one tunnel for each traffic direction. Each tube comprises three 11.5-ft wide lanes, a 1.6-ft right shoulder, and a 2.6-ft left shoulder, designed to serve as an emergency passageway. This configuration ensured capacity, safety, and operational efficiency in one of the city's most significant urban transport infrastructures.

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Underground works

Bank Station Capacity Upgrade

London, United Kingdom

Located at the heart of the City of London 's financial district, Bank Station is one of the capital's most important transport hubs and a strategically critical piece of infrastructure for urban mobility and the UK economy. It is a key interchange station for Transport for London (TfL), used by more than 100,000 passengers, accounting for nearly 400,000 journeys per weekday, particularly during peak hours. The efficient operation of Bank Station is essential for both the London Underground (LU) and the Docklands Light Railway (DLR) networks. Within this context, the Bank Station Capacity Upgrade (BSCU) project was conceived to significantly improve accessibility, passenger circulation,and interchange, delivering a 45% increase in capacity during peak hours while substantially reducing journey times.

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Underground works

REM Project

Quebec, Canada

The Réseau Express Métropolitain (REM) is an ambitious light rail system designed to transform mobility across the Greater Montreal area. The project comprises a 41.63-mile double-track network, with 26 stations distributed across four branches, and represents one of the largest public transport developments ever undertaken in Canada. Within this framework, DRAGADOS has participated in the construction of a 2.24-mile tunnel excavated using a tunnel boring machine, connecting downtown Montreal with the airport. Excavation was carried out using a 24.18 ft diameter EPB TBM, initially through water-bearing soils, mainly silty sands, followed by mixed-face conditions transitioning into hard massive rock. In its final section, the tunnel passes beneath one of Montreal Airport's runways, requiring rigorous geotechnical and operational control.