The state-of-the-art tunnel boring machine, which commenced operations from Katechaki, has to date excavated a tunnel measuring 5.1 kilometers in length and is expected in the coming days to achieve the so-called “breakthrough,” namely the demolition of the shaft wall at the junction of Vasileos Konstantinou and Michalakopoulou streets. This represents a pivotal technical and construction milestone, marking the successful completion of a major section of the underground alignment.
A distinctive feature of the project is that “Athena” is not limited to tunnel excavation alone, but simultaneously carries out the full lining of the tunnel. For every 1.5 meters of excavation, a prefabricated concrete ring is installed, effectively delivering a fully completed tunnel. To date, 3,393 rings have been installed, while the volume of excavated material exceeds 400,000 cubic meters.
Approximately 300 workers are employed on the project overall, operating in 24-hour shifts under the AVAX–GHELLA–ALSTOM construction consortium, in close cooperation with Elliniko Metro.
At the same time, the second tunnel boring machine, “Niki,” is advancing from the opposite direction. Having started from Veikou Grove, it has already constructed 2,960 meters of tunnel, covering approximately 42% of the total 7.5-kilometer route. It is currently located just beyond the Kypseli Square station and will continue beneath the Courts complex, Alexandras Avenue, Exarchia, Akademias Street, and Kolonaki, with the Evangelismos shaft also as its final destination.
According to the project schedule, once tunnel excavation is completed, construction of the stations will commence. Approximately 65% of the total tunnel length of Line 4 has already been completed, which constitutes the largest public infrastructure project currently under construction in the country.
Upon completion of its mission, “Athena” will be dismantled, retrieved to the surface, and stored for future use, underscoring the high level of expertise that has been developed in Greece in the field of underground infrastructure.