Webuild has completed the Casalnuovo Tunnel on the high-speed/high-capacity (HS/HC) Naples–Bari railway line, marking a significant milestone for the project and for tunnelling innovation in Italy. The tunnel, built for Rete Ferroviaria Italiana (RFI – FS Italiane Group), is the first in the country to be constructed using hyperbaric excavation.
Hyperbaric excavation marks engineering first for Italy
Located along the Naples–Cancello section, the 650-metre tunnel was excavated continuously, day and night, through a densely populated area. The hyperbaric method used pressurised air to displace groundwater, allowing works to take place in dry conditions. This technique also reduced environmental impacts, as it avoided the use of cement mixes and chemical additives.
“All the means used to excavate were electric, with zero emissions,” Webuild confirmed, highlighting the sustainable approach to the complex engineering work.
The tunnel was completely sealed and divided into watertight compartments. Workers entered through a compensation chamber that gradually increased pressure, enabling them to safely adapt to the hyperbaric environment. Strict health protocols and continuous monitoring ensured worker safety throughout the process.
“This was possible thanks to this innovative technique that has been used a few times, even at a European level,” said Webuild, calling the tunnel a best practice in underground construction.
Track installation progress on Naples–Cancello section
Track laying on the Naples–Cancello section began in February and is progressing steadily. More than 10 km of track have already been laid, with completion expected by the end of summer. This section forms part of the broader HS/HC Naples–Bari line, aimed at drastically reducing journey times between the two cities.
Once the Naples–Cancello and Cancello–Frasso sections open at the end of 2025, journey times between Naples and Bari will be reduced from four hours to just two hours and 40 minutes—without the need to change trains.
New station access and future operational milestones
From early 2026, the activation of the Naples–Cancello section will enable high-speed trains to reach Napoli Afragola station. New stations at Acerra and Casalnuovo will also come into operation, extending access to high-speed rail for communities across the Naples metropolitan area, including Casoria, Afragola, Caivano and Acerra.
“When fully operational, [Napoli Afragola] will become a strategic hub to connect the North and South of Italy and regional and national transport systems,” said Webuild.
Strategic role in TEN-T Network and Southern Italy connectivity
Once completed, the 145 km-long high-speed line will include 15 tunnels, 25 viaducts and 20 stations or stops. The full route will reduce travel times significantly: Naples to Bari in two hours, Rome to Bari in three hours, and Rome to Lecce or Taranto in four.
The project is a key component of the Scandinavian–Mediterranean Corridor of the Trans-European Transport Network (TEN-T), enhancing connections between southern and northern Italy and to wider European transport systems.
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