Four empty coaches of express trains were gutted at the maintenance yard in Basin Bridge railway station on Saturday.
Railway officials and police officers attributed the fire to a possible electrical short circuit.
Police said that around 8.45 a.m., railway employees noticed that a fire had broken out in the sleeper coach of the Ganga-Kaveri Express that was in the shed for maintenance. Within minutes, the fire spread to two adjoining air-conditioned coaches of the same train.
Two coaches of a nearby train, Kaveri Express, were also burnt.
The employees at the yard immediately alerted senior railway officials including the senior section engineer of Southern Railways, S. Kannappan, who is in-charge of the yard, as well as the railway police and fire service.
Fire and rescue service personnel from the Madras High Court, Washermenpet and Pulianthope then arrived, and battled the blaze for over an hour, before putting it out.
Based on a complaint from Mr. Kannappan, a case of accidental fire has been registered by the railway police.
Officials said both express trains had come to the yard for routine maintenance check-ups, including electrical and mechanical repairs, on Saturday morning.
The Ganga-Kaveri Express was scheduled to depart from Chennai Central at 5.40 p.m. on Saturday, while the Kaveri Express was leaving at 9 p.m. The gutted coached were replaced with spare ones and the trains ran as per schedule, an official said.
“We suspect an electrical short circuit caused the fire, but a probe has been launched into the incident by both Southern Railways and the government railway police,” said a police officer.