The cause of the derailment, which occurred around 9.30 am, is yet to be ascertained, Metro Railway sources said. A departmental inquiry has been ordered into the incident.
Though no passenger was injured, some complained of uneasiness as lights went off inside the compartments immediately after the accident, police sources said. A passenger was taken ill and was treated at the Medical College Hospital, they said. Panic-stricken passengers, who were evacuated through the driver's cabin door by the police and fire brigade personnel, protested over frequent snags in the metro rail services in the city.
Metro Railway sources said railway staff and Railway Protection Force personnel also lent a helping hand in evacuating the passengers.
Services were maintained between Maidan and Kabi Subhas station and arrangements were being made to resume services between Dum Dum and Girish Park station.
On October 12, Sobhabazar station of the metro railway was ransacked by passengers who were angry over the malfunctioning of train doors and consequent delay in the services.
