Thursday night's Metro scare on the Dum Dum-bound train at the Mahatma Gandhi Metro station was triggered from a piece of aluminum foil, part of a duct of the air conditioning system, which caused the explosion-like sound, and the ensuing panic at the Metro station.
"When we first determined that the cause of the accident was a piece of aluminum foil, we began to investigate as to how it got on the third line. We didn't rule out chances of a passenger or Metro official throwing it onto the line. Finally, we discovered that the piece was supposed to be fitted to one of the ducts located right above the north western edge of the platform," a senior Metro official disclosed.
However, Metro officials refused to comment on the status of the investigation. "The report is due on Monday. We cannot comment until the report is officially submitted," said Metro spokesperson, Protyush Ghosh. Around 9pm on Thursday, just as the train was pulling out of the MG Road station, there was a big explosion in the third compartment. Soon the lights went off and smoke engulfed the dark compartments.
Primary investigations revealed that the piece of aluminum had been sandwiched betwnrfeeen the third rail and one of the compartments. When the train began to move the current collector started conducting electricity from the third rail, causing friction. This resulted in a mechanical fault in the electrical network.
"We formed a team comprising security experts, to find how the aluminum foil reached the third rail. The piece of aluminum fell down right on the edge of the platform. Since the aluminum fell from a height, it gained momentum and rebounded off the edge of the platform and fell on the third rail," the official added.
When Metro officials determined that the aluminum foil was a part of the air conditioning system they canned the CCTV, which corroborated the fact that it was detached from the mouth of the duct and fell onto the rails.