Athens Metro Line 1, historically known as the ISAP or "Electric Railway," is the oldest and most iconic line in the city's network, connecting Piraeus to Kifissia. To ensure the continued reliability and safety of this century-old artery, a massive upgrade and renovation program was launched. NAMA played a central role in this multi-million euro project, delivering the critical construction studies and engineering expertise required to modernize the line while maintaining its continuous operation.
With a construction budget of nearly €130 million, the project focused on the total renovation of the railway infrastructure, ensuring the line meets modern high-speed and safety standards.
Complex Engineering in a Historic Environment
The renovation of Line 1 presented unique challenges, particularly the need to work within the "old" tunnel sections and alongside active urban environments. NAMA’s multidisciplinary contribution included:
- Railway Infrastructure Upgrades: NAMA completed construction studies for the substructure and superstructure of 23.3 km of double railway line. This involved the renovation of the section from Neo Faliro to Kifissia, providing modern track-laying plans according to strict authority standards.
- Tunnel Strengthening and Structural Innovation: A critical component was the structural strengthening of the historic tunnel between Omonia and Monastiraki. NAMA designed specialized track slabs, including both embankment-based slabs and "floating slabs" designed to minimize vibrations in the city center.
- Electrification and Systems Integration: The project included the replacement of aging electrification structures from Monastiraki to Attiki and Nea Ionia to Kifissia. These new systems were integrated into the Automatic Train Surveillance (ATS) control systems to enhance operational precision.
- Hydraulic and Geotechnical Engineering: NAMA provided essential hydraulic studies for flood protection and geotechnical studies to ensure the stability of the track beds and tunnel walls across varying soil conditions.
- Operational Continuity: NAMA developed typical arrangements for railway line diversions, allowing construction works to proceed without fully shutting down the vital transit services for the public.
Impact on Urban Transit and Sustainability
The modernization of Line 1 has significantly improved the commuting experience for thousands of daily passengers. The key outcomes of the project include:
- Increased Speed and Safety: The new track superstructure allows for higher operational speeds and a smoother ride, while the upgraded signaling ensures the highest safety levels.
- Vibration Reduction: The use of floating slab technology in dense urban sections has dramatically reduced noise and vibration levels for the historic buildings situated above the tunnel.
- Extended Life-Cycle: Through structural strengthening and the modernization of E/M systems, the lifespan of this historic infrastructure has been extended for several decades, preserving its role as a sustainable transport backbone for Athens.
For NAMA, the Line 1 project highlights our expertise in the rehabilitation of existing infrastructure. It demonstrates our ability to apply modern engineering solutions to historic assets, ensuring that the legacy of the Athens Metro evolves alongside the needs of the modern city.
