ITD’s Chennai Metro TBM Peacock Records Line-4’s 1st Breakthrough

ITD Cementation India today celebrated tunnel boring machine (TBM) S-1074B’s first breakthrough at Kodambakkam Ramp on Chennai Metro’s 26.1 km Line-4 which will connect Poonamallee Bypass – Light House via 30 stations.

TBM S-1074B (Peacock) is a refurbished Herrenknecht Earth Pressure Balance (EPB) machine which was previously deployed as Krishna-2 by CEC-ITD-Tata JV to build 3 tunnels for Package UGC-04 of Mumbai Metro’s 33.5 km Line-3 (Aqua Line) between 2017-2020.

The machine passed factory acceptance tests (FAT) at Herrenknecht’s Tamil Nadu plant in March 2023, and then launched on May 2, 2024 from Line-4’s Panagal Park Crossover towards Kodambakkam Ramp Retrieval Shaft near Meenakshi College, covering a distance of 2047m for the down-line tunnel.

TBM Peacock is actually Line-4’s fourth TBM to start tunneling as part of the 116.1 km Chennai Metro Phase 2 project, but the very first to complete its first tunneling assignment.

Along the way, TBM Peacock passed TBM Pelican (S-1075B) which was launched months prior in January 2024 to work on the parallel up-tunnel. Peacock passed through extremely challenging geological conditions, including a sharp curve with a 205m radius.

Per CMRL’s press release, “the main challenge for this tunnel boring was that it had to pass through 190 no’s of building mostly residential out of which more than 50 no’s of buildings were old buildings. Also the TBM had to bore parallel to the active railway line before crossing the multiple railway tracks. The TBM also passed through two churches and below the Kodambakkam flyover. This is the longest tunnel of phase 2 with 2.047 km has been achieved without any disturbance to the public and existing traffic.“

Chennai Metro Rail Ltd (CMRL) had awarded ITD Cem with Line-4’s two underground contracts for packages UG-01 (5.15 km) & UG-02 (4.87 km) in January 2022 with a combined contract value of Rs. 3743.24 crore and 48 month deadline.

The scope of 4.877 km Package UG-02, where Peacock has been deployed, includes building twin tunnels connecting Kodambakkam Ramp to Boat Club Station with 5 stations at Kodambakkam Flyover (formerly Meenakshi College), Kodambakkam, Panagal Park (with a crossover), Nandanam and Boat Club (Adyar Gate Junction).

A video of the breakthrough can be viewed here on CMRL’s X page.

Chennai’s Line-4 consists of roughly 16 kms of TBM tunnels (up & down line) for which ITD Cementation has deployed 4 machines. Here’s a brief status of each. I’ll add an update with progress details if and when available.

• S-1352A (TBM Flamingo) on UG-01 – Started tunneling in September 2023
• S-1073B (TBM Eagle) on UG-01 – Started tunneling in mid-January 2024
• S-1075B (TBM Pelican) on UG-02 – Commissioned at Panagal Park’s Crossover in January 2024
• S-1074B (TBM Peacock) on UG-02 – Recorded first breakthrough today (this post!)

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– TMRG