Supervision services for the construction works of Barcelona Metro Line 9

Barcelona Metro Line 9 runs almost entirely in a tunnel, with a total length of more than 40 km. This project was a great challenge for all the engineering companies involved, due to the geological heterogeneity of the terrain and the innovative technology required for the construction.

Tunnels have been excavated with TBM and EPB tunneling machines, depending on the rock and soil conditions. Barcelona subsoil is mainly composed of alluvium, granite with different degrees of alteration, sand, gravel and clay. Therefore, two different types of tunnel were designed. The first one was a twin-tube tunnel with a smaller tube diameter, and the second one was a single-tube double-track tunnel with a larger tube diameter and integrated stations.

The length of the twin-tube tunnel is 14 km (with an I.D. of 8.32 m) and the length of the single-tube tunnel is 28.20 km (with an I.D. of 10.90 m). Additionally, Line 9 comprises 52 stations, including 20 interchange stations in order to facilitate connections with other modes of transport.

In conclusion, the construction of Barcelona Metro Line 9 has required the development of rather innovative methods within the tunneling sector. On the one hand, integrated stations have been built within the single-tube tunnel. On the other hand, synchronized sliding doors have been installed to exit the trains in order to increase metro safety and efficiency. Finally, the project also involved the construction of deep shafts, which represent an innovation within the civil engineering sector.


GISA (Infrastructure Management Authority of Catalonia)

Project Dates

2001 – ongoing

Project Figures

Contract Value:
41,936,221.30 €