A goods train carrying high-speed diesel caught fire on Sunday morning near Tiruvallur, a Railway official said.
The fire broke out in a wagon and quickly spread to others.
No casualties have been reported, the official said.
Fire tenders have been rushed to the spot and overhead power supply for train services has been suspended.
“As a precautionary measure, local train services have been temporarily suspended. Also, 8 express trains have been cancelled and 5 other trains diverted and 8 trains short-terminated,” Southern Railway said in a statement.
Railway officials are actively managing the situation at the site. Restoration work is in progress and normal train operations will resume at the earliest, the statement said.
The cause of the fire is not immediately known, the official added.