Metro 3: Of proposed 33.5 km stretch, tunnelling over in 10 km

All 17 tunnel boring machines have been lowered into construction sites

The Mumbai Metro Rail Corporation Limited (MMRCL), which has undertaken the Mumbai Metro-3 project (Colaba-Bandra-SEEPZ) lowered all 17 tunnel boring machines (TBMs) into construction sites on Monday. This marks the completion of 10.455 km of tunnelling work of the proposed 33.5 km of the Metro 3 corridor by the second week of October.

“Tunneling work is progressing satisfactorily and with the last, the 17th, TBM in the underbelly of the city we will work with more enthusiasm,” said SK Gupta, director (projects), MMRC.

Ashwini Bhide, managing director, MMRCL, tweeted, “MMRC commences lowering

of TBM Tansa 2 of package 3. With this, all 17 TBM are underground and poised to complete the tunnelling soon by following stringent safety and quality norms.”

This marks the completion of 10.455km of tunnelling work of the proposed 33.5km of the Metro 3 corridor by the second week of October.

The TBMs have been named after the rivers flowing in the state, Tansa, Vaitarna, Surya, Krishna, Tapi, Wainganga and Godavari. Krishna 1 was the first TBM to be lowered at Naya Nagar station on September 18, 2017, and has completed the maximum amount of tunnelling, 1.727 km, as

compared to other TBMs.

Each of these TBMs weigh around 7,000 tonnes, with a diameter of 5.8 metres and length of 98 metres long and have been imported from STEC (China), Terratec Ltd (Australia), Herrenknech AG (Germany), and ROBBINS (USA). After being assembled at the Metro casting yards, the machine is lowered from a launching shaft using a heavy duty crane with a capacity of 750 tonnes. The 33.5-km-long underground corridor will run on the Colaba-Bandra-SEEPZ stretch and have 27 stations, of which 26 will be underground and one ‘at grade (interchanging) station’.