Police said the incident happened at 9.30am on a railway in front of Wat Koh Kaew in Tambon Kamang.
The man was identified as Atthapol Maiyawan, 34, from Surin. He fainted shortly after the incident.
Narit Puksor, the driver of the Bangkok-bound train from Lop Buri, parked his train after the incident. He told police that he saw a man sitting with his legs hanging over the track so he opened the train’s whistle to signal the man to move away.
Narit said he tried to stop the train after the man did not move but the train was running at full speed and its momentum prevented it from stopping in time.
Police suspect the man intended to commit suicide.