The colossal tunnel boring machine (TBM) excavating the central section of Barcelona’s L9 and L10 metro lines has reached Carrer de Sant Gervasi de Cassoles, marking a significant milestone in its journey towards Lesseps station. This achievement keeps the ambitious infrastructure project on track, with officials aiming to complete the current tunnelling phase this autumn.

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The machine has advanced 265 metres since its reactivation at the future Mandri station, according to sources from the Department of Territory, Housing and Ecological Transition who spoke to 20 Minutos. Authorities are closely watching its progress, as the TBM was out of action for over a year following a breakdown of its cutting wheel. The successful restart and steady advance have renewed confidence in the Catalan government’s ability to meet challenging timelines for what will be one of Europe’s longest automated metro lines.

A Complex Engineering Feat

The 100-metre-long, 12-metre-diameter machine has now passed beneath Carrer de Muntaner, clearing the construction shaft for the future Mandri station. It is now burrowing through the dense urban landscape of the Sarrià-Sant Gervasi district, a complex task requiring careful planning and execution. The current section between Mandri and Lesseps covers a total of 1.6 kilometres.

Engineers face significant geological challenges here. The new cutting wheel, which arrived at the Port of Barcelona last July, was specifically adapted to bore through a mix of granite, slate, and sandstone. According to engineering firm SOCOTEC, involved in the project, the TBM can advance a maximum of 20 metres per day under ideal conditions. This highlights the scale of the undertaking.

In response to this progress, the Generalitat de Catalunya and the Barcelona City Council have scheduled an informative session for local residents. The meeting will provide updates on the project’s progress and detail technical building inspections underway before tunnelling.

The Path to Completion

While the TBM’s progress is a critical step, it represents just one component of a much larger city-wide effort. The Catalan government, led by President Salvador Illa, considers the completion of the L9/L10 central section a strategic priority. Work also advances on several future stations, including Campus Nord, Manuel Girona, Sarrià, and Sanllehy. Further north, the section between La Sagrera-TAV and Guinardó | Hospital de Sant Pau should be operational by the end of 2027. This project runs parallel to other major transport works in the city, such as the extension of the L8 FGC line.

The Conselleria, headed by Sílvia Paneque, expects the full, unified line to be operational by 2032. Once complete, the L9 and L10 lines will form a single system connecting five of the region’s most populous municipalities: Barcelona, Santa Coloma de Gramenet, Badalona, L’Hospitalet de Llobregat, and El Prat de Llobregat.

This will create a direct public transport link between key hubs like Josep Tarradellas Barcelona-El Prat Airport and Badalona, revolutionising mobility across the metropolitan area. Projections suggest the completed lines will serve 113 million passengers annually, a significant increase from the 27 million currently using the operational northern and southern segments. Officials also estimate the new line will remove approximately 8,000 cars from the city’s roads daily.

Securing the Investment

To fund this vast project, the Catalan government has earmarked €40 million for the L9/L10 central section in its proposed 2026 budget, currently awaiting approval in Parliament. However, officials acknowledge this amount is insufficient to cover total costs.

To accelerate the construction of the remaining stations, the Generalitat is exploring public-private partnerships. The government has opened a market consultation to gauge interest from construction firms, investment funds, and financial entities regarding potential public works concessions. Minister Sílvia Paneque stated in February that this model could speed up station works without altering the overall 2032 completion date for the line, which first began partial operation in 2009.