Police cordoned off the platform where the explosion took place, rushed forensic experts, bomb disposal squads and sniffer dogs to look for clues and Tamil Nadu government transferred the investigation to its specialised wing CB-CID.
The train continued its onward journey after railway authorities replaced three damaged coaches while other trains were being operated as scheduled after a brief disruption, railway officials said. The police are probing all angles including whether the bomb was planted after the train entered the city railway station or elsewhere, a police official requesting anonymity said.
CB-CID sleuths who have already begun the probe, detained three coaches of the train, collected pellets found on the scene and other materials, sources said.
The Tamil Nadu police have alerted railway authorities at various stations from Bangalore to Chennai to look for CCTV footages for suspects and also the point at which the explosive material found its way into the train, sources said.
Two persons, who were travelling by the train, have been detained for questioning, police said but refused to reveal further details.
State DGP K Ramanujam, who visited the mishap site, said “it is a minor blast. It is suspected that Chennai could not have been a target of those who were behind the blast because the train was running late. Some other location could have been the target”.
“It is premature to say what kind of device was used in the blast. Damage to the train is not heavy,” he added. DGP (Elections) Anoop Jaiswal said “we are picking up clues and any speculation on this is too premature. Nobody has been arrested so far”, he said.
