Tunnel-boring for E-W Metro to be completed by Q1 of 2021

Kolkata: The tunnel-boring work for East West Metro is expected to be completed by the first quarter of 2021.

"Tunnel Boring Machine (TBM) 1 has stopped working and it will not be in use again. Basically, it has sunk and it is in the wrong position. TBM 2 will be installed under Nirmal Chandra Street," said Leonard John Endicott, a geotechnical expert and head of the international expert committee appointed by the Kolkata Metro Rail Corporation Limited (KMRCL).

Tunnel-boring work was put on hold after a machine hit an aquifer on August 31, 2019 at Bowbazar area, leading to severe ground subsidence and collapse of nearby buildings.

Before the Bowbazar mishap, two TBMs were working in parallel, boring tunnels for the up and down lines of the East West Metro corridor.

"It will take around 5 months for the TBM to go up to Sealdah from Bowbazar. Thereafter, it will take three months for the TBM, which is a huge machine, to turn around. It will take another two months for the machine to dig on the other side and reach up to the point where the first TBM had cut the tunnel. Underground tunneling work for the East-West Metro corridor is likely to take 10 more months to be completed," pointed out Endicott, the geotechnical expert.

It may be mentioned that the Calcutta High Court had on February 11 allowed resumption of tunnel-boring work for the East-West corridor.

Accepting a report by IIT-Madras, the court's division bench directed the KMRCL, the executing agency for the project, to restart operations in Bowbazar, in consultation with the institute.

The bench, comprising Chief Justice T B N Radhakrishnan and Justice Arijit Banerjee, had in September last year ordered suspension of tunneling work until further orders.

"During the last five months, we were very busy and doing the inspection of the work. The damaged TBM, which is a 'write-off', will be dismantled and taken away from the underground shaft. After thorough inspection on Tuesday, we have started adding steel plates to stop inflow of water and soil. This apart, the new team is slightly larger than earlier. Some people have been replaced and new people have been included in some key positions," said Guy Bridges, a member of the committee.

However, the first phase of the East-West Metro, stretching five kilometres between Salt Lake Sector V and Salt Lake Stadium, was thrown upon to public on February 14, 2020. The total stretch of the East-West Metro, from Salt Lake Sector V to Howrah Maidan, spans 16.5 kilometres.