Mumbai Metro Line 7A’s TBM Dhruv Starts Tunneling at CSIA

J Kumar Infraprojects (JKIL) on Saturday commissioned their second tunnel boring machine, T60, for Mumbai Metro Red Line’s 3.17 km Line-7A (Gundavali – CSIA) at Chhatrapati Shivaji International Airport’s Terminal 2 Station.

Nicknamed TBM Dhruv, this Ø6.68m dual-mode Terratec machine was previously deployed in 2018-2021 by J Kumar – CRTG JV on Mumbai Metro Line-3’s 4.94 km package UGC-05 (Dharavi Station – CSIA T1) and 4.45 km package UGC-06 (CSIA T1 – Marol Naka).

The machine’s parts were extensively refurbished at J Kumar’s yard on Ghodbunder Road (view on Google Maps) over the past year and started to get lowered at CSIA Terminal 2 Station’s shaft in July 2023.

For Line-7A’s Package CA-48, TBM Dhruv will build an approximately 2.49 km line for the down-line tunnel from CSIA’s Terminal 2 towards Airport Colony Station and onwards to a ramp on the Western Express Highway (WEH).

T60 Dhruv (top) and temporary rings built by T62 disha (bottom) – Photo by Harish Gaikwad

Mumbai Metropolitan Region Development Authority (MMRDA) had awarded J Kumar Infraprojects with Package CA-48’s Rs. 1,998 crore contract in September 2019.

Their scope of work, besides the 11.38 km elevated Line-9, includes building Line-7A’s viaduct, ramp and underground tunnels and 2 stations at Airport Colony and CSIA Terminal 2, where it’ll meet the under construction Line-3 (Aqua Line), and in the future Line-8 (Gold Line) linking to Navi Mumbai International Airport.

Indicative Route Map of Mumbai Metro’s Line-7A – view Mumbai Metro map & information

Meanwhile, TBM Disha (Terratec T62) working on the parallel up-line tunnel since September has completed its initial drive of building 60 rings and come to a pause. Its back-up gantry is currently being attached to start mining activities for its main drive.

Backup gantry being sent through the up-line tunnel – Photo by Ittirit Khemasiri
Back-up gantry inside the tunnel – Photo by Pawan Maurya

As shared earlier, at this time I see Line-7A becoming operational no sooner than mid-2026 looking at the performance of Aqua Line’s TBMs around the airport that I’ve tracked, and the standard system installation and station development work required to make the line fit for revenue operations.

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Global traveler who prefers mass rapid transit

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