Kolkata Metro created history on Wednesday when its rake ran through a tunnel under a river for the first time in the country, a senior official said in Kolkata.
The metro rake which had only officials and engineers on board ran under the Hooghly from Kolkata to Howrah on the other side of the river.
This is a “revolutionary step” in providing a modern transport system to the people of Kolkata and its suburbs, the official said.
Metro Railway general manager P Uday Kumar Reddy travelled from Mahakaran station in Kolkata to Howrah Maidan station of the East West Metro corridor in the rake.
Later, another rake also reached Howrah Maidan station by the same route.
Terming it a ‘historic event', the Metro general manager said, “Trial runs between Howrah Maidan and Esplanade station will be conducted for the next five to seven months, following which regular services on this stretch will begin.”
Trial runs on the 4.8 km stretch of the underground section will commence soon, Reddy said.
"We want to be thorough, don't want to rush into the services," he told reporters at a press conference.
Stating that it is the deepest rail network in India, he said that it requires a lot of skill and hard work to construct and run it.
After this stretch becomes operational, Howrah Maidan will be the deepest Metro station -- 33 metres below the surface -- of the country.
The metro is expected to cover the 520-metre stretch under the river Hooghly in 45 seconds, the official said, adding that this tunnel under the river is 32 metres below the water surface level.
The East West Metro corridor connecting Howrah Maidan and Sector V, the Information Technology hub in Salt Lake, is partially operational - between Sealdah and Sector V stations.
Completion of the total project has been delayed owing to accidents in Bowbazar area of central Kolkata.
"We took a decision, instead of waiting for the whole route to be cleared, we have focussed on the route that is clear now," Reddy said.
The Metro Railway had earlier said that it plans to start services by the end of this year in the Howrah Maidan to Esplanade stretch if a problem persisting at Bowbazar, between Esplanade and Sealdah stations, is not sorted by then.
On August 31, 2019, a tunnel boring machine had hit an aquifer leading to severe ground subsidence and the collapse of a number of buildings at Bowbazar.
Several houses were damaged again in May 2022, owing to ground subsidence caused by water seepage during work for joining the tunnels coming from the Sealdah side in the east and the Esplanade side on the western side.
The underground water seepage caused cracks in 12 buildings at Madan Dutta Lane in Bowbazar on October 14, 2022, the last accident there to affect completion of the project.
Out of the 16.6 km length of East West Metro, the underground corridor constitutes 10.8 km between Howrah Maidan and Phoolbagan with the tunnel passing below the Hooghly river, while the rest is elevated corridor, according to an official of Kolkata Metrol Rail Corporation, the executing agency of the East West Metro corridor.
Stating that the construction of the tunnel from Howrah Maidan to Esplanade had to face several challenges, the Metro GM said that some emergency measures also had to be taken to overcome those.
The tunnel passes through very congested areas along the Brabourne Road in the Burrabazar area with several century-old houses there and the Metro had to shift residents to hotels during underground work there.
All the staff and engineers of KMRC, under whose efforts and supervision the underwater engineering marvel has been achieved are joyous that their dream has come true, said KMRC managing director H N Jaiswal.
