TBM Breakthrough On Line 7A Marks Completion Of MMRDA’s First Underground Metro Tunnel In Mumbai

The Mumbai Metropolitan Region Development Authority (MMRDA) has marked a significant milestone with the successful breakthrough of Tunnel Boring Machine (TBM) 'Disha' on Metro Line 7A.

This achievement completes a 1.647 km underground tunnel connecting Andheri East to Chhatrapati Shivaji Maharaj International Airport (CSMIA), the first of its kind constructed by MMRDA in Mumbai's metro network.

The event was attended by Maharashtra Chief Minister Devendra Fadnavis, Metropolitan Commissioner Sanjay Mukherjee and other dignitaries.

"Historic Breakthrough for Mumbai Metro! Today, April 17, 2025, 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!," said an official MMRDA statement.

"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," it added.

Metro Line 7A, a 3.4 km extension of the operational Dahisar East–Andheri East corridor (Line 7), includes a 2.5 km underground stretch.

Once complete, it will offer direct access to CSMIA Terminal 2 and seamless interchanges with Metro Lines 1, 6, and 9.

Tunnel work began in September 2023 and moved ahead smoothly despite challenging geological conditions, including steep gradients and overburden depths as low as 1.5 metres.

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