It happened at Golden State Boulevard and Maple Avenue just before 3 pm on Sunday.
A CHP sergeant says witnesses reported that a man driving a car did not stop at a stop sign before starting to cross the tracks.
His car was hit by a Union Pacific train, which the conductor said was going about 30 miles per hour at the time.
First responders removed the victim from the car and tried to revive him, but he died at the scene.
Investigators say it's unknown at this time if drugs or alcohol were involved.