The Conci Triangle

In the photo, a Webuild specialist technician carries out precision operations inside one of the hydraulic thrust systems of the TBM, which will install the structural precast tunnel lining segments. 1/1

In perfect synergy between human expertise and machine power, the giant tunnel boring machine advances deep into the mountain, leaving behind, step by step and piece by piece, a concrete lining. These are the conci – precast concrete segments that turn an excavation into a high-precision railway tunnel. The project to double and upgrade the Palermo-Catania-Messina railway line finds its most powerful engineering expression in this invisible circuit: on one side the precision of the workers inside the TBM as they guide the steel shield forward; on the other, the creation of a fully integrated industrial supply chain rooted directly in the region. The segments installed underground are produced in automated factories built in Sicily, where earth and rock excavated from the tunnels are reused and transformed into high-strength structural elements. Each ring installed is another step toward connecting the three corners of the Palermo–Catania–Messina triangle, reducing travel times and bringing Sicily’s railway network – historically defined by single-track lines – into the major corridors of sustainable European mobility.

Facts & Figures

A turning point for the island: today in Sicily, out of 1,370 kilometers of existing railway lines, 1,146 kilometers are single-track. With around 200 kilometers of new infrastructure, travel times will be reduced from three hours to two on the Palermo–Catania route, and from 75 to 45 minutes between Catania and Messina.

The numbers underground: more than 110 kilometers of the new line will run entirely through tunnels. The conci are being produced directly in Sicily in three dedicated factories, which reuse excavation materials such as sand and gravel and manufacture the required volume of segments. Around 400 segments are needed for every 100 meters of tunnel.

Employment and economic impact: the overall investment amounts to €12 billion. The lots awarded to the Webuild Group are generating around 6,800 jobs.