The Bangalore Metro Rail Corporation Limited (BMRCL) has started lowering parts of four tunnel boring machines (TBMs) inside the shafts at sites of the proposed Cantonment and Shivajinagar Metro stations. From Thursday onwards, with the help of cranes, giant components of TBMs, such as cutter heads and middle shields, will be lowered.
The BMRCL had imported the machines from China. After reaching the Chennai port, they were transported in trucks and arrived in the city between February and March. Due to the lockdown, the BMRCL had halted construction work for a while, but resumed projects on April 23.
At present, approximately 950 people are working on the underground line from Vellara Junction to Tannery Road.
The four tunnel boring machines are called Avani, Urja, Lavi and Vindhya. BMRCL Managing Director Ajay Seth said, “The machines are being assembled and site testing is being done by contractor engineers.”
In phase II, for the first two packages from Vellara Junction to Tannery Road, the BMRCL is deploying four TBMs. Among the four TBMs, two machines will tunnel from Cantonment Station to Shivajinagar. After completing the task, the machines will be deployed back to Cantonment towards Tannery Road metro station. The other two machines will build a tunnel from Shivajinagar towards Vellara Junction.
Mr. Seth said that the TBM work will need three years. Commissioning of the line may require another year.
Amidst the lockdown and migration of employees in lakhs in trains, the BMRCL, through its contractors, has managed to retain 6,000 construction workers in the city. An official said that around 2,400 to 2,700 workers have left the city to their hometowns in northern parts of the country.
Under phase II, the BMRCL is building a tunnel network from Dairy Circle to Nagawara wherein the total length of the UG line is 13.92 km.
In total, nine TBMs will be used in the second phase. The city had first witnessed tunnelling work in May 2011, in the first phase of Namma Metro, where the BMRCL had deployed two machines (Helen and Margarita) to build a tunnel from Majestic to Cubbon Park metro station.