Fire broke out in the engine of an air-conditioned rake of the Kolkata Metro on Thursday, causing dense smoke that left 16 passengers ill, officials said.
Some of those who were taken ill, fell unconscious and were admitted to a nearby hospital.
The incident took place in a Dum Dum-bound train around 5pm soon after it left the Maidan station.
Disaster management personnel along with those of the fire and emergency services department rescued the passengers, the officials said.
"A lot of smoke was seen as soon as the train left Maidan station. We understood since there is smoke, there must be fire somewhere," Metro Railway CPRO Indrani Banerjee said.
"We switched off the power connection and took steps to douse the fire. We have rescued all the passengers and there has been no casualty," she added.
Many commuters alleged that there was no response from the metro control room even after repeated calls were made to the helpline.
The passengers also claimed that they had to break window panes for ventilation inside the coach.
"We were trapped inside the metro for more than an hour. Most of the elderly passengers face breathing problems due to suffocation," said a passenger.
"We shouted for help but there was no response from the authorities. Some of us then broke window panes to ensure that there was some sort of ventilation," another passenger said.
In a tweet, metro authorities said truncated services are now running between Central to Noapara and Mahanayak Uttam Kumar to Kavi Subhash.