The Athens Suburban Railway (Proastiakos) is a vital component of the capital’s transportation network, linking the metropolitan center with the international airport, the port of Piraeus, and key regional hubs like Chalkida and Kiato. A cornerstone of this network is the section between Treis Gefyres and the Acharnes Railway Center (SKA), a high-capacity corridor that handles both suburban commuters and national mainline traffic.
NAMA was responsible for the comprehensive engineering design of this technically demanding 4.8 km section, ensuring the seamless integration of a quadruple railway line into a dense urban environment.
Engineering Mastery in a Live Rail Environment
The Treis Gefyres – SKA project was defined by its extreme technical complexity, requiring the expansion of the existing rail corridor without interrupting the constant flow of trains. NAMA’s multidisciplinary contribution included:
- Quadruplex Railway Design: NAMA completed the full railway design for a 4.8 km quadruple-track system. This configuration allows for the separation of suburban and long-distance national traffic, significantly increasing the capacity and speed of the network.
- The Agioi Anargyroi Cut & Cover: A standout feature of the project is the 1,872-meter long "Cut & Cover" tunnel. This underground section was designed to minimize the railway's impact on the local community, reducing noise pollution and reconnecting urban spaces that were previously severed by surface tracks.
- Complex Operational Phasing: To keep the railway operational during construction, NAMA designed and managed six distinct phases of temporary track deviations. This ensured that the vital "Athens-Thessaloniki" link remained open while the new infrastructure was being built.
- Structural and Geotechnical Excellence: NAMA provided specialized structural studies for the tunnel and retaining works, as well as geotechnical investigations to manage the soil conditions throughout the urban corridor.
- Hydraulic Protection: Integrated hydraulic studies were conducted to ensure advanced flood protection and stormwater drainage for both the surface tracks and the underground tunnel sections.
Key Figures and Strategic Importance
The completion of the Treis Gefyres – SKA section transformed the efficiency of the Greek rail network:
- Corridor Capacity: The quadrupling of the tracks at this bottleneck allowed for a dramatic increase in the frequency of trains, supporting the daily transit of tens of thousands of passengers.
- Strategic Hub (SKA): The project feeds directly into the Acharnes Railway Center (SKA), the most important rail junction in Greece, where the North-South mainline meets the East-West suburban axis.
- Urban Integration: By placing nearly 2 km of the railway underground at Agioi Anargyroi, the project provided the municipality with new surface-level public spaces and parklands, significantly improving the quality of life for residents.
For NAMA, the Athens Suburban Railway project demonstrates our ability to deliver large-scale, multidisciplinary transport infrastructure in high-stakes environments. By solving the challenges of a quadruplex railway and a major urban tunnel, we helped create a faster, more reliable, and community-friendly rail backbone for the city of Athens.
