The green signal from the state government is expected to expedite the construction of the underground section of the Joka-BBD Bagh Metro corridor (Purple Line), said railway officials.
Two tunnel-boring machines (TBM) have already been lowered in a launching shaft built inside St Thomas’ Boys’ School in Kidderpore. The TBMs arrived from Germany via the state of Tamil Nadu. They were dismantled and sent to Calcutta on trailers.
“The parts have been lowered into the shaft. Assembly and testing are underway. The first machines should start constructing the tunnel from the second week of July,” said an official of the RVNL, the implementing agency of the Purple Line.
“One TBM will start boring first. The second one will be deployed after the first has already bored around 150m. It means the second machine will start working more than a month after the first,” the official said.
The corridor is now functional on an 8km, elevated stretch between Joka and
Majerhat. The next stop, Mominpore, will be the last elevated station and Kidderpore, the first underground station.
“The nod from the state government was eagerly awaited. If we had to bypass Kidderpore, there would have been several design challenges. Now that the clearance has come, work should gain momentum,” the official said.
Sources in the RVNL said work was already underway in full swing between Majerhat and Mominpore and between Kidderpore and Esplanade. “There has hardly been any progress in the Mominpore-Kidderpore stretch. Now, that is going to change,” said one of them.
The shaft inside St Thomas’ Boys’ School is 17m deep. The TBMs are around 90m in length and each weighs over 600 tonnes.
In the first phase, the TBMs will construct the tunnel to the Victoria Memorial, a distance of around 1.7km. In the second phase, they will link Victoria and Park Street, a distance of just under 950m.
The stretch between Park Street and Esplanade will be done through the traditional cut-and-cover method.
“The construction of the tunnel from Kidderpore to Victoria should be completed by June 2026, if things go according to plan,” he added.
The state government’s alleged refusal to allow construction at Alipore’s Bodyguard Lines had stalled the construction of the Kidderpore station.
The area will be used to build ventilation shafts and entry and exit structures, shift utilities, and for traffic diversions, said RVNL engineers.
After a series of negotiations and a revised station layout, a breakthrough came during a recent meeting between railway representatives and senior officials at the state secretariat.
On June 26, the commissioner of Kolkata Municipal Corporation sent an email to the chief project manager for the RVNL for the Purple Line, giving the go-ahead subject to certain conditions.
RVNL was awarded the contract for Kidderpore, Victoria, Park Street and Esplanade stations in September 2023.
The duration of the contract was four years.
No one in the agency was willing to give a new timeline for the completion of the
project.
“From the time work starts at Kidderpore station, four years will be needed to complete the job,” an engineer said.
The Purple Line was 14km long between Joka and Esplanade. Recently, Metro Railway has received the nod for an extension till Eden Gardens in the north and IIM Joka in the south. The corridor will now be just over 18km long.
