Mumbai Metro network's 1st underground tunnel completed by MMRDA on Line 7A

A breakthrough was achieved on Thursday as a boring machine deployed for Mumbai Metro Line-7A dug a 1.647 km long underground tunnel here between Andheri (East) and the city airport, officials said.

The Tunnel Boring Machine (TBM), named Disha, achieved the breakthrough close to Bamanwada in Andheri (East), in the presence of Maharashtra Chief Minister Devendra Fadnavis, completing the first underground tunnel in Mumbai's Metro network by MMRDA, they said.

The Mumbai Metropolitan Region Development Authority (MMRDA), the project implementing agency, in a post on X said the breakthrough was a "monumental milestone" and an "engineering marvel".

The 1.641 km long tunnel, with a diameter of 6.35 metres, has been dug for the extension of the existing Metro line 7 between Dahisar (East) and Andheri (East) till the Chhatrapati Shivaji Maharaj International Airport.

The line will provide another Metro connection to the International Airport and offer interchange to other Metro lines as well, as per the MMRDA.

Its commissioner Dr Sanjay Mukherjee, additional commissioners Vikram Kumar and Ashwin Mudgal and other dignitaries were also present on the occasion.

The approximately 3.4 km long Metro Line 7A alignment is partially elevated and runs parallel to the Western Express Highway and Sahar elevated road.

The TBM started excavation of a tunnel for the underground portion of the Metro corridor, which is an extension of the existing Metro Corridor 7, in September 2023, as per the MMRDA officials.

"This marks a monumental milestone as the Tunnel Boring Machine (TBM) for Metro Line 7A achieves its breakthrough, completing the first underground tunnel in Mumbai's Metro network by MMRDA! This engineering marvel, spanning 1.647 km, connects Andheri (East) to Chhatrapati Shivaji Maharaj International Airport (CSMIA) with a finished diameter of 6.35 m," the MMRDA said post in a post on X.

On Wednesday, the MMRDA started conducting trials on the Mandale to Diamond Garden section of Metro Line 2B, spanning from DN Nagar in the western suburbs to Mandale, Mankhurd, in the eastern suburbs.