Passengers of the train escaped unhurt as the motorman managed to stop the train when he felt uncomfortable, Eastern Railway (ER( spokesman R N Mahapatra said.
"He felt uncomfortable and fell down from his cabin, sustaining serious head injury and became senseless," Mahapatra said.
"I Halder, the driver of 37913 Up Howrah-Katwa local stopped the train after passing Daihat station near gate no 20/1 at 11.12 am when he felt uncomfortable," he said.
The train left the site for its onward journey to Katwa with a new driver and guard, Mahapatra added.
Two EMU locals were delayed owing to the incident.
An enquiry has been initiated into the incident, which occurred at around noon today.