The head of the Department of Public Works and Territorial Policy of the regional government of Catalonia, Joaquín Nadal, and the mayor of Terrassa, Pere Navarro, were the distinguished witnesses to the conclusion of the excavation work by one of the two EPB TBMs working on the two-tube tunnel in the "Rambla to Can Roca" section of Terrassa Tunnel, part of the project to extend Catalonian railway lines that FCC is performing for Gestió d'Infraestructures, S.A. (GISA), in a joint venture with OHL and COPISA.

There are two parallel 3,150-metre-long tunnels with an excavation diameter of 6.9 metres. They are sheathed with 30-centimetre-thick concrete segments of tunnel lining and connected to one another by eight smaller cross-tunnels whose walls are shotcrete over a structure of wire mesh and trusses. The excavation cuts through a widely varying range of terrain types formed in the Quaternary period and the Miocene epoch, where clay and silt predominate, dashed through sporadically with sand and gravel.

The average depth of earth covering the tunnel's layout is between 14 and 20 metres, with a few exceptions such as the intersection with the existing RENFE tunnel and under the Torrent de Valparadís, where the covering layer is no more than five metres deep.