Mumbai Metro Line 7A reached a major milestone with the successful breakthrough of the second and final tunnel of the corridor connecting Andheri (East) to Mumbai airport, the Mumbai Metropolitan Region Development Authority (MMRDA) said.
The final tunnel of the corridor connects Andheri (East) to Chhatrapati Shivaji Maharaj International Airport (CSMIA).
The upline tunnel marks a key development in the project, which began on November 4, 2023 using a Tunnel Boring Machine (TBM).
The tunnel is about 1.65 km long and required the installation of 1,178 rings, each measuring 1.4 metres in length, the officials said on Tuesday.
The finished tunnel has a diameter of 5.6 metres, lined with precast ring segments made up of six parts.
The construction team overcame several engineering challenges during the tunnelling process. These included crossing beneath Metro Line 3, passing under the Sahar Elevated Road ramp, and safely tunnelling near major underground sewer and water pipelines.
The line will include two stations — Airport Colony and CSIA Terminal 2 — and is designed to integrate with the operational Metro Line 3 (Aqua Line). In the future, it will also connect to Metro Line 8 (Gold Line), which will link to Navi Mumbai International Airport.
According to officials, so far, the project has achieved 61 per cent completion across the full alignment.
The Mumbai Metro Line 7A is a part of an extension of Metro Line 9 which is also called Red Line.
The breakthrough is a significant step toward improving connectivity between the airport and suburban areas of Mumbai through a modern and efficient metro system, officials said.
MMRDA officials have expressed satisfaction with the progress and praised the efforts of the workers and engineers involved in the project.
In April, the Tunnel Boring Machine (TBM) working on the Mumbai Metro Line 7A corridor had achieved the first breakthrough, completing a key section of the underground tunnel on the route.
The breakthrough marks the completion of a 1.647-kilometre-long tunnel between Andheri (East) and Chhatrapati Shivaji Maharaj International Airport (CSMIA). This tunnel, with a finished diameter of 6.35 meters, is the first underground tunnel constructed by the Mumbai Metropolitan Region Development Authority (MMRDA) as part of its metro network.
