A fire broke out in an AC rake between Rabindra Sadan and Maidan stations in Kolkata on Thursday evening.
Fifty passengers were injured in the incident and about 16 of them fell unconscious, according to local websites.
The injured have been admitted to SSKM hospital.
Metro services between Mahanayak Uttam Kumar and Kavi Subhash stations and between Esplanade and Dumdum metro stations have resumed.
West Bengal Fire Service and Kolkata Police Disaster Management group have started rescue operations to evacuate all the passengers.