A Brooklyn man was killed relieving himself between the cars of a 6 train, police sources said Tuesday.

The victim, 63, boarded the train at 6:50 a.m. March 8 and urinated between the last two cars. When the train turned, the man hit his head on the door handles and was killed.

He wasn’t discovered until over an hour later when his friend, who was watching his bags, told the MTA he was lying between two cars.

Workers then discovered him at the Pelham Bay Park stop, the end of the line.