Regular trial of trains on the 4.8 km stretch between Esplanade and Howrah Maidan will start soon, the Kolkata Metro informed in a tweet.

Soon after the successful run, Kolkata Metro General Manager P Uday Kumar Reddy described it as a historic moment for the city of Kolkata.

Kolkata is also the city where India's first metro service started way back in 1984.

The section of the tunnel that stretches 520 meters under the Hooghly River will be the main point of interest for both KMRC officials and railway enthusiasts across India.

Once the trains have crossed the river, they will then pass through Howrah station, which is the deepest metro station in the country, located 33 meters below the ground.