The train had a trial run on Sunday from Hat Yai to Sungai Kolok, SRT deputy governor Thanongsak Pongprasert said.
Last Saturday, a bomb exploded on the railway track in Pattani's Khok Pho district which led to derailment of the train and severely damaged the rear carriage. One railway official was killed and three others were wounded.
The train was leaving Sungai Kolok district in Narathiwat province and heading for Hat Yai in Songkhla province when the explosion occurred.