Chennai (Metro Rail News): Chennai Metro advanced as Larsen & Toubro (L&T)’s TBM Adyaar (S-1326A) achieved its first breakthrough for Package TU-02 at Adyar Junction on Line 3 for Chennai Metro Phase 2 spanning 116.1 km.
This is the fourth tunnel breakthrough in 12 km Package TU-02 which connects Kellys and Taramani Road Junction stations on Line 3. This entire corridor covers a 45.8 km distance through 49 stations (20 elevated & 29 underground).
TBM Adyar ( S-1326A)
TBM S-1326A, nicknamed TBM Adyar is a 100m long Ø6.65m Herrenknecht earth pressure balance (EPB) machine. IN July 2022, TBM Adyar passed factory acceptance tests (FAT) at Herrenknecht’s Alinjivakkam facility.
For its first assignment (current), TBM Adyar was deployed at Greenways Road Station in April 2023 and it constructed a 1218 m tunnel for the upline.
The TBM achieved a breakthrough in 22 months due to difficult mixed geological conditions. TBM Adyar constructed an approx 300 m tunnel below the Adyar River.
TBM Adyar is 1 of 8 machines commissioned by L&T for constructing twin tunnels from Kellys to Taramani Road Junction stations spanning 12 km ( total 24 km).
Package TU-02
L&T bagged Package TU-02 from Chennai Metro Rail Ltd. (CMRL) at Rs. 2385 crore in May 2021 with a 42-month deadline.
The scope of work under this Package includes the construction of twin tunnels between Kellys and Taramani Road Junction. In addition, the contract also includes the construction of diaphragm walls, entry/exit structures of Chetpet Station, Royapettah Government Hospital Station, Thiruvanmiyu Station, and part diaphragm wall of Greenways Road Station, including launching and retrieval shafts at the above stations.
Chennai Metro Line-3 Tunnel Breakthroughs
With this breakthrough, a total of 10 breakthroughs have been achieved so far for Line 3.
South-Side (L&T – Package TU-02: Kellys to Taramani Road Junction)
| Month & Year | TBM Name (ID) | Breakthrough Location | Tunnel Length (m) |
| August 2024 | Siruvani (DZ1040) | Sterling Road | 703 |
| September 2024 | Kaveri (S-1327A) | Adyar Junction | 1228 |
| October 2024 | Palar (DZ1041) | Sterling Road | 700 |
| February 2025 | Adyar (S-1326A) | Adyar Junction | 1218 |
North-Side (Tata Projects – Package TU-01: Madhavaram to Kellys)
| Month & Year | TBM Name (ID) | Breakthrough Location | Tunnel Length (m) |
| June 2023 | Anaimalai (S98) | Venugopal Nagar | 415 |
| August 2023 | Nilgiri (S96) | Madhavaram High Road | 1400 |
| September 2023 | Servarayan (S99) | Venugopal Nagar | 415 |
| November 2023 | Podhigai (S97) | Madhavaram High Road | 1400 |
| June 2024 | Anaimalai (S98) | Otteri Station | 925 |
| August 2024 | Kolli (S81B) | Otteri Station | 903 |
