Astaldi to Lead Italian Works on Brenner Base Tunnel

Italian construction group Astaldi has taken a leading role in building the Italian section of the Brenner Base Tunnel, a flagship Alpine rail project intended to transform freight and passenger links between Italy and northern Europe.

Major contract for Mules 2-3 lot on Italian side

Publicly available company information shows that Astaldi heads a joint venture appointed to deliver the “Mules 2-3” construction lot, which covers the bulk of the underground works on the Italian side of the Brenner Base Tunnel. The contract, valued at around 1 billion euros, assigns Astaldi a stake of just over 42 percent in a consortium that includes several Italian and international partners.

The Mules 2-3 lot extends from the Mezzaselva area north of Fortezza to the Austrian border, encompassing the two main rail tubes and associated service galleries. Project documentation indicates that this lot is responsible for excavating and lining approximately 40 kilometers of tunnels, making it one of the largest civil‐engineering packages currently underway in Italy.

Reports on the project describe the Italian section as technically demanding, with works taking place at depths of more than a kilometer beneath the Alpine surface. Complex geology, high overburden and the need to coordinate excavation methods with Austrian contractors on the opposite side of the border have all shaped Astaldi’s construction strategy.

The contract also involves extensive logistical infrastructure, including access tunnels, caverns for crossovers and ventilation, and underground construction sites that must operate year‑round in high mountain conditions.

Key role in cross-border breakthrough beneath the Alps

The significance of Astaldi’s role has come into sharper focus with the recent breakthrough that physically linked the Austrian and Italian tunnel sections beneath the Brenner Pass. Information released by project stakeholders indicates that the Austrian H53 Pfons–Brenner lot has now connected to the main tunnel tubes of the Italian H61 Mules 2-3 lot, creating continuous twin rail tunnels between the two countries.

On the Italian side, the breakthrough followed the completion of mechanical excavation using tunnel boring machines that advanced north from Mules toward the border. On the Austrian side, contractors relied primarily on conventional excavation with controlled blasting. The junction point lay roughly 1,400 meters below the mountain surface, underscoring the scale and complexity of the works undertaken by Astaldi’s joint venture on the Italian section.

This cross‑border link comes after an earlier connection of the exploratory gallery, which runs between and below the two main tubes and will later serve as a service and drainage tunnel. With both the exploratory tunnel and the main tubes now joined at the frontier, Italy’s portion of the core underground structure is largely in place.

Project updates indicate that further fit‑out, tracklaying and systems installation will still be required over the coming years before the tunnel can open to traffic. However, the structural continuity achieved through the Mules 2-3 lot marks a decisive engineering milestone for the entire Brenner corridor.

Technical challenges and construction methods on the Italian section

Astaldi’s works on the Italian side combine mechanized tunneling with conventional excavation, chosen according to rock conditions and alignment geometry. Publicly available technical summaries describe the deployment of large tunnel boring machines for long, relatively straight stretches of the main tubes, while drill‑and‑blast techniques are used for more complex junctions, caverns and access drifts.

The geology beneath the Brenner Pass is characterized by gneiss and other hard rocks, with varying fracture patterns and groundwater conditions. These factors require sophisticated support systems, including rock bolts, shotcrete, and prefabricated lining segments designed for high overburden pressures. The Italian contract also includes numerous cross passages between the two main tubes, a safety requirement that adds to the volume of underground construction.

Ventilation and logistics present additional challenges. Construction ventilation systems must handle both dust and exhaust gases in long headings, while maintaining safe working conditions deep underground. At the same time, a continuous flow of materials, equipment and personnel must be managed through a limited number of access tunnels and shafts, particularly at the main worksite near Mules.

Despite these complexities, reports from the project promoter indicate that excavation performance on the Italian side has remained robust, contributing to the successful cross‑border breakthrough and maintaining momentum toward the tunnel’s next phases.

Strategic importance for European north–south rail

The Brenner Base Tunnel is designed as a low‑gradient rail link forming the core of the Scandinavian–Mediterranean transport corridor, one of the European Union’s priority trans‑European networks. By lowering the maximum gradient compared to the existing Brenner mountain line, the new base tunnel aims to shift a significant share of freight traffic from road to rail and to cut journey times for passenger services between Italy, Austria and Germany.

Astaldi’s contract on the Italian section supports this broader strategy by delivering a key segment of the continuous underground route between Fortezza and Innsbruck. Once completed, the tunnel is expected to handle a substantial increase in rail capacity across the Alps, reducing congestion and environmental impacts associated with heavy truck traffic on the Brenner motorway.

Transport studies referenced in public planning documents project that the completed tunnel could accommodate longer and heavier freight trains while allowing for more frequent passenger services. The result is expected to be a rebalancing of modal share in favor of rail, aligning with European climate and mobility goals.

Regional stakeholders in Trentino–Alto Adige and Tyrol have highlighted the project’s potential to reduce noise and air pollution in valley communities currently affected by transit traffic. Astaldi’s progress on the Italian underground works is therefore seen as directly linked to long‑term quality‑of‑life improvements on both sides of the border.

Economic impact and next steps for the Italian works

The Mules 2-3 lot ranks among the most valuable infrastructure contracts awarded in Italy in the past decade, with Astaldi’s share representing a sizable portion of its construction backlog at the time of signing. The works have generated hundreds of jobs in specialized tunneling, engineering, logistics and site support, together with indirect employment in local services.

As excavation milestones are reached, attention is progressively shifting toward secondary lining, waterproofing, and preparation for the installation of rail infrastructure and safety systems. According to project updates, upcoming activities on the Italian section will include completion of cross passages, reinforcement of key caverns and the progressive demobilization of heavy excavation equipment as the focus turns from rock removal to outfitting.

The overall Brenner Base Tunnel project is targeting commissioning in the early 2030s, subject to coordination with access line upgrades in Italy, Austria and Germany. Astaldi’s performance on the Italian underground works will be a central factor in keeping the core tunnel schedule aligned with these broader corridor improvements.

For travelers and freight operators, the eventual opening of the Brenner Base Tunnel is expected to reduce north–south journey times and offer a more reliable, weather‑resilient connection beneath the Alps. Astaldi’s construction of the Italian section marks a pivotal contribution to that future transport landscape.