An AC Metro rake was evacuated on Friday after its airconditioning system malfunctioned and the passengers complained of suffocation.

The snag caused Metro disruption for around two hours.

The train had left Dum Dum at 11.12am. Passengers alleged the airconditioning was not functioning from the start but the driver continued to run the train till MG Road. Metro drivers’ cabins have computerised panels that indicate whether anything is malfunctioning on the train.

The previous train to New Garia had been cancelled. As a result, this train was overcrowded and the atmosphere inside soon turned unbearable because of the sealed windows.

“Usually, one can feel the airconditioning kick in minutes after the train leaves Dum Dum,” said daily commuter Tarun Banerjee. “But today, it was not working at all and it was extremely suffocating from the start.”

Banerjee, who takes the train to Central station each day, got down at Girish Park, unable to bear the suffocation. “I thought I’d faint,” he said.

Class XII student Suvam Mitra, who had boarded the train from Dum Dum to go to Tollygunge, said: “A number of passengers were feeling unwell and got down at Girish Park. But the driver continued to run the train even though the passengers were finding it difficult to breathe.”

“Somebody in our coach pressed the alarm at MG Road. After the doors opened, there was an announcement for passengers to get off. There was an altercation between some of the passengers and the driver,” Suvam said.

A witness said some passengers refused to get down and the train had to be taken to Chandni Chowk after a 10-minute stop at MG Road. This caused a disruption in services.

The rake was taken to the maintenance shed. Officials said in the evening that they were yet to identify the snag that caused the airconditioning to malfunction.

Metro officials claimed that the airconditioning was “inadequate”. “The blowers were operational and so there was no chance of suffocation,” said an official.

“An inquiry is on to find out what caused the snag,” said Metro general manager P.B. Murty.

The train was Calcutta Metro’s first AC rake to roll out of the Integral Coach Factory at Perambur near Chennai last October.

Doctors said passengers could have fallen seriously ill in the stuffy environment. “Those who suffer from claustrophobia, lung problems and cardiac ailments could have had complications,” said critical care expert Subrata Maitra.