The passengers were evacuated, and a truncated service was being run from Kavi Subhas to Girish Park stations.
Senior metro railway officials, Railway Protection Force (RPF) personnel, disaster management teams and a Kolkata police contingent were at the spot.
"The incident took place as the power supply from the third rail had stopped. Since power from the third trail is required for the metro to run, the train automatically came to a stop. The passengers were evacuated," said Indrani Banerjee, Chief Public Relations Officer, Kolkata Metro Railway.