Vaitarna-1 first TBM on Metro 3 corridor to complete tunnelling.

On Friday, Vaitarna-1, the Tunnel Boring Machine (TBM) of package 2 of the Colaba-Bandra-SEEPZ Metro 3 corridor, completed its longest downline tunnel drive of 3.814 km from Azad Maidan to Mumbai Central Metro station.

This was the 15th TBM breakthrough in the Metro 3 corridor, and Vaitarna-1 became the first TBM in the corridor to complete its entire length of tunnelling.

A Metro 3 spokesperson said the machine completed its operation in 20 months at an average of 190 metres every month and installed 2,720 rings. The 6.68-m, 817-tonne dual-mode TBM, which began its mission on December 4 last year, had passed the factory acceptance testing in July 2017, and arrived at the Mumbai port in mid-September. It was lowered into the Azad Maidan shaft for assembly on December 4 last year.

The spokesperson said, “Vaitarna-1 made its way through hard basalt and breccia rock mass with some pockets of very low strength shale bands at average depths of below 20 metres from the road level. It marks an important milestone of the 33.5-km-long underground Metro 3 corridor.”

Package 2 is being implemented by a consortium of HCC-Mosmetrostroy Joint Venture and is the first package of this project to complete one entire tunnel drive. The spokesperson said, “There were many operational challenges encountered during this drive as Vaitarna-1 went past many heritage, old and dilapidated buildings. In all, there are 169 structures in the influential zone, including 14 high-rise buildings and 28 heritage structures.”

Chief Secretary Ajoy Mehta and Western Railway general manager Anil Kumar Gupta were present to witness the milestone. Ashwini Bhide, managing director, Mumbai Metro Rail Corporation (MMRC), termed the task challenging. She said, “The successful completion makes us confident of completing the project on schedule. We are progressing well on work on stations.”

The Mumbai Central Metro station will provide direct and easy access to two major commuting hubs: Mumbai Central depot and Mumbai Central station. As of Friday, the MMRC has completed 31 km of tunneling with 17 TBMs commissioned through 10 shafts.

THE HINDU