An NIA team arrived at the site where the Mysore-Darbhanga Bagmati Express collided with a stationary freight train.

A possible sabotage angle is being investigated, prompting the arrival of the NIA team, police said.

Twelve coaches of the express train were derailed in the accident on Friday.

The Government Railway Police of Korukkupet have registered a case.

Meanwhile, Tamil Nadu Deputy Chief Minister Udhayanidhi Stalin criticised the Union Government, saying the latter should take steps to prevent train accidents.

Southern Railway General Manager R. N. Singh remarked that the Mysore-Darbhanga Express entering the loop line, despite signals being set for the main line, was "unusual".

Interacting with the media persons after visiting the accident site, Singh reiterated that the situation was unusual, with the train diverting to the loop line even though it was supposed to follow the main line.

Sources within the Railways told that the incident occurred due to a signal failure.

Train No. 12578, the Mysore-Darbhanga Express, had been given a green signal to pass through the main line. However, while travelling at 75 km/h, the train entered the loop line and collided with the rear of a stationary goods train.

The express train crossed Ponneri railway station at 8.27 p.m. and was cleared to proceed to the next station, Kavaraipettai, via the main line.

A statement from Southern Railway said, “While entering Kavaraipettai station, the train crew experienced a heavy jerk, and instead of continuing onto the main line as signalled, the train diverted to the loop line at 75 km/h and collided with the goods train.”

Railway officials confirmed that the crew remained unharmed, and the fire in the parcel van was put out.

"No casualties have been reported so far, some people were injured. All injured passengers have been taken to nearby hospitals," an official stated.

Train movement on both sides of the section has been affected, and alternative arrangements are being made for passenger transportation.