3 min readMumbaiApr 17, 2025 05:10 PM IST
First published on: Apr 17, 2025 at 05:10 PM IST
The Mumbai Metropolitan Region Development Authority (MMRDA) Thursday achieved a tunnel breakthrough on Mumbai Metro Line 7A, between Andheri East and Chhatrapati Shivaji Maharaj International Airport. Chief Minister Devendra Fadnavis ceremonially carried out the breakthrough by pushing the lever in the presence of MMRDA Metropolitan Commissioner Dr Sanjay Mukherjee.
The 3.4-km long Line 7A is an extension of the currently operational Red Line 7: Dahisar East to Gundavali in Andheri East. While 2.5 km of 7A will be underground, 0.94 km will be elevated, with two stations, Airport Colony (elevated) and CSMIA Terminal 2 (underground). On completion, the corridor will also offer connectivity from Mira-Bhayander to the airport, joining through Metro Lines 9 and 7.
A tunnel boring machine (TBM) named Disha made the breakthrough after finishing the 1.647-km downline tunnel drive, which started in September 2023. The TBM, which started from a depth of 30 metres, has encountered a series of engineering difficulties throughout its underground course, such as passing across Metro Line 3, tunnelling under the Sahar elevated road ramp, and passing by major utilities such as water mains and sewage pipes.
The completed tunnel connects the city’s north-south and east-west metro corridors, facilitating smooth transfers to Metro Line 1 (Versova–Ghatkopar) and he Metro Line 3 (Colaba-Seepz) through the underground station.
“It was thrilling to watch this tunnel breakthrough which is a part of the most important confluences of Mumbai Metro in the airport area. I should call this an engineering marvel for getting this tunnel through a difficult patch underground. And with such milestones, it will be our effort to open about 150 km of Metro lines by next year,” said Fadnavis during the breakthrough ceremony.
MMRDA, along with J Kumar Infraprojects Limited (JKIL), IIT Bombay and Brihanmumbai Municipal Corporation (BMC), utilised advanced methods such as micro-tunnelling, TAM grouting — for underground soil reinforcement and continuous monitoring instrumentation to meet unforeseen soil strata and unmapped utilities. In a few areas, the TBM functioned with only 1.2 metres of cover under subways while ensuring maximum safety at all times.
“The arrival of Disha at the Bamanwada retrieval shaft marks a huge step in the delivery of th Mumbai Metro Tunnel,” said Dr Nalin Gupta, managing director of JKIL, who led the project.
The Airport Authority of India (AAI) transferred the necessary land in October 2021, and later, around 200 hutments from places such as Bamanvada and Vile Parle were rehabilitated to give space for the project.
As of now, the physical construction of Metro Line 7A is at a level of 59 per cnet. According to sources, the line is expected to open to the public by December 2026. On completion, it will decongest road traffic to the airport and offer direct metro connectivity to the new Navi Mumbai International Airport through the integrated metro system through Metro Line 8.
With Lines 1, 2A, and 7 already up and running, and others such as 2B, 4, 5, 6, 9, and 12 currently under various construction stages, the 337-km Mumbai Metro project is slowly but surely taking shape.
Maharashtra CM Devendra Fadnavis attends the Mumbai metro line 7A- tunnel breakthrough event, at Vile Parle east in Mumbai.
(Express Photo/Sankhadeep Banerjee) 
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