ITD’s Chennai Metro TBM S1075B Passes Factory Tests

Tunnel boring machine manufacturer Herrenknecht on Tuesday completed factory acceptance tests (FAT) on S-1075B, their fourth and final machine for 26.1 km Line-4 of the 116.1 km Chennai Metro Phase 2 project.

Back in 2017-2020, this 110m long Ø6.67m diameter Earth Pressure Balance machine, then branded as S-1075 and nicknamed Krishna-3, was deployed by CEC-ITD-Tata JV to build 3 tunnels for Package UGC-04 of Mumbai Metro’s 33.5 km Line-3 (Aqua Line).

Following its final breakthrough at Worli Station in March 2020, it was dismantled and taken to Herrenknecht’s Tamil Nadu plant in Thiruvallur District’s Alinjivakkam Village for refurbishment.

The machine, now rebranded as S-1075B, will be deployed by ITD Cementation for Line-4’s 10 km underground section between Power House Ramp – Light House Station. This section consists of roughly 16 kms of TBM tunnels (up & down line).

More specifically, the machine will be deployed to construct tunnels on 4.87 km Package UG-02 connecting Kodambakkam Flyover – Boat Club at a maximum depth of 26m.

Per CMRL’s press release, the machine will be lowered into Panagal Station’s launch shaft in October 2023 from where it’ll first tunnel east to Nandanam to build the down-line and get retrieved from Kodambakkam Flyover by September 2024, which sounds a little too ambitious to me.

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

ITD in December 2022 had cast the 1st of roughly 9000 tunnel segments at their Muthukadu Casting Yard along ECR Road.

With this development, FAT for all 4 machines of Line-4 is now complete!

• S-1073B had passed FAT in January 2023 (UG-01 ; refurbished)
• S-1074B had passed FAT in April 2023 (UG-02 ; refurbished)
• S-1352A had passed FAT in May 2023 (UG-01 ; new)
• S-1075B passed FAT just yesterday! (UG-02 ; refurbished)

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– TMRG