The section covered by this study is Lot 6, which extends for 38 km between the provinces of Enna and Catania and is in an advanced stage of completion; the track laying has already been completed. In compliance with regulatory guidelines and circular economy principles, maximum attention was paid to reusing excavated materials during construction activities. This approach has yielded significant benefits, including reducing waste production, optimizing the use of natural resources, and minimizing the environmental impact related to transportation, making the project a model of environmental sustainability even during the construction phase.

To maximize the reuse of materials and improve the geotechnical properties of the soils, the technique of lime stabilization was adopted on approximately 776,000 m³ of excavated earth and rocks. This practice transforms excavated materials, otherwise destined for disposal, into suitable resources, which in this particular case were used for the construction of railway embankments.

The process, regulated by the RFI Specification (2017), involves the following operational phases:

• Soil preparation: stripping of the surface soil and treatment of the laying plane
• Lime procurement: safe delivery and storage of the material
• Lime dosing and spreading: use of specific machinery to ensure uniformity
• Soil-lime mixing: milling and humidification for homogeneous treatment
• Transport and laying of the mixture: uniform distribution on the construction site
• Compaction and finishing: optimization of the density of the treated material

These operations allow for a rapid chemical reaction between lime and soil, with short- and long-term benefits, including:

• Improved workability: reduction of soil plasticity and water sensitivity.
• Increased durability: greater resistance to weathering, erosion, and frost.
• Optimization of mechanical strength: the treated soil acquires properties comparable to the best natural mixtures, making it suitable for bearing heavy loads.

Italferr, through collaboration between the Lot's Works Management and the Sustainability Operational Structure, conducted a detailed analysis to quantify the environmental impacts of lime stabilization, comparing this technique with a traditional construction scenario originally planned in the project, based on the use of virgin quarry materials.

The analysis focused on greenhouse gas (GHG) emissions and was based on the Italferr Methodology, which allows, at the project scale, to estimate the climate footprint of a project in accordance with ISO 14064-1. For the application of the Methodology and the comparison between the two scenarios, both field data and project information were necessary. The results highlighted significant benefits in terms of GHG, showing a 62% difference between the two scenarios, in favor of lime stabilization. In summary, this technique has allowed for the mitigation of approximately 16,400 tons of CO2e.

A remarkable result that demonstrates how sustainability is a concrete reality in action today and how Italferr is actively contributing to the FS Group's decarbonization goals.

Other notable benefits:

• Reduced heavy traffic: Thanks to the reduction in supplies, over 70,000 truck trips were avoided, significantly decreasing road congestion and improving safety by reducing the risk of accidents related to heavy transport.
• Respect for local agriculture: A fundamental element of the project was the multispectral monitoring of agricultural areas near the construction site. Thanks to advanced technologies, it was possible to ensure the health of crops and protect them from potential negative impacts. This monitoring, however, did not reveal any particular critical issues during construction activities.
• Environmental protection: The reduction of environmental impacts goes beyond greenhouse gas emissions, with benefits manifesting in various areas. A significant example is the decrease in the release of microplastics into the environment, resulting from reduced tire wear, contributing to the preservation of human health and ecosystems in general.

Lime stabilization thus represents a valid example of a circular economy. This is one of many examples demonstrating that it is possible to build efficient and environmentally friendly railway infrastructures, contributing concretely to the ecological transition.

The synergy between our internal teams and the adoption of sustainable practices confirms Italferr as an example of excellence in the railway sector. We are proud to continue building a future where engineering meets environmental protection.