Portuguese 
Refurbished tunnel boring machine from Italy had its 12 heaviest components transported over roads, sea, and waterways; the cutter head alone weighs 170 tons.
The Houda tunnel boring machine, a machine weighing approximately 2,000 tons and 10 meters in diameter, arrived in Gennevilliers, a suburb of Paris, after a logistics operation covering over 2,200 kilometers. Reused from another section of the Grand Paris Express, the equipment will excavate seven kilometers of the future Line 15 West.
The machine did not arrive assembled at the new site. Its 12 heaviest components were transported separately from Italy, combining road, sea, and river transport. Among these pieces is the cutter head, a circular structure weighing 170 tons responsible for breaking the ground during excavation.
According to a joint statement from NGE and Webuild, released on August 26, 2026, Houda will operate in batch 2 of Line 15 West, between Saint-Ouen and Courbevoie. The contract is valued at €1.38 billion (about US$1.5 billion) and also includes four stations and supporting structures.
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Tunnel Boring Machine Houda Will Have Two Separate Routes
The seven kilometers planned will not be excavated in a single continuous advance. The machine will depart from the service structure Les Cabœufs in Gennevilliers and will carry out two routes in different directions.
In the first route, the machine will advance 1.2 kilometers between Gennevilliers and Saint-Ouen. It will then be prepared to proceed in the opposite direction, excavating another 5.8 kilometers between Gennevilliers and Courbevoie.
During the second phase, Houda will pass by the future stations Les Grésillons, Les Agnettes, Bois-Colombes, and Bécon-les-Bruyères. The equipment will also cross under the Seine River twice during its new mission.
Once fully assembled, the tunnel boring machine will measure over 100 meters in length. In addition to the 170-ton cutter head, the logistics operation also involved a main drive unit weighing about 130 tons.
Components Traveled by Sea and the Seine River
Before arriving in France, the machine was fully refurbished at specialized Webuild facilities in Italy. The work included renewing components and incorporating monitoring and maintenance technologies.
The 12 heaviest pieces departed from the port of Civitavecchia, located near Rome. The cargo initially traveled by sea before entering French waterways, navigating the Seine to the port of Gennevilliers, on the outskirts of Paris.
A Webuild report on the journey indicates that choosing water transport avoided the need to cross the Alps with the heaviest components.
According to NGE and Webuild, the refurbishment saved approximately 12 months compared to the time required to manufacture a new tunnel boring machine. The companies also attribute reductions in resource consumption, costs, and emissions associated with the project to the reuse of the equipment.
Machine Has Already Excavated 5.8 Kilometers of Line 16
Houda was not exclusively manufactured for Line 15. The tunnel boring machine began its first mission on the Grand Paris Express in 2020 when it was used for the construction of Line 16.
In this work, the equipment excavated 5.8 kilometers between Aulnay Val Francilia and Sevran-Livry in the Seine-Saint-Denis department. After completing the section, the machine was disassembled and sent to Italy for refurbishment and adaptation to the conditions of the new route.
The reuse is part of a project aimed at expanding the transport network in the Île-de-France region. The full Line 15 will be approximately 75 kilometers long, with 36 stations, forming a circular link around Paris, allowing for movement between municipalities in the metropolitan area without the need to cross the city center.
Excavation will produce about 500,000 cubic meters of earth
The new mission of the tunnel boring machine is expected to remove approximately 500,000 cubic meters of material from underground. NGE and Webuild estimate that 80% of this volume will be transported by waterway, reducing truck traffic on the region’s roads.
The companies project that the use of vessels could prevent about 64,000 truck trips. A large portion of the excavated material is also expected to be directed towards recycling processes.
The tunnel lining will require approximately 23,000 prefabricated segments. It is estimated that 79% of these pieces will be produced with fiber-reinforced concrete, a solution that, according to the project managers, reduces the amount of steel needed by half compared to traditional methods.
Line 15 West remains under construction, with service expected to begin in 2031. The Société des grands projets schedule stipulates that the section will connect Pont de Sèvres to Saint-Denis–Pleyel.
Once operational, the journey between La Défense and Saint-Denis–Pleyel is expected to take around 19 minutes.
