Tunnel boring machine manufacturer Herrenknecht on Friday completed factory acceptance tests (FAT) on S-1074B, their 2nd of 4 machines for 26.1 km Line-4 of the 118.9 km Chennai Metro Phase 2 project.
Back in 2017-2020, this 110m long Ø6.67m diameter Earth Pressure Balance machine, then branded as S-1074 and nicknamed Krishna-2, 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 Dadar Station in October 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-1074B, 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 29m.
Per CMRL, the machine will be lowered into Panagal Station’s launch shaft in October 2023 from where it’ll tunnel east to Nandanam to build the down-line and get retrieved from Boat Club by September 2024, which sounds a little 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.
With this development, FAT for 2 more TBMs are now pending – 1 refurbished and 1 new machines. The refurbished machine will be S-1075 from Mumbai’s Line-3, while the new machine’s serial number still remains unknown to me.
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