Ohio State Highway Patrol of the Findlay Post said the crash happened Wednesday at 1:43 p.m. on US 68, south of US 30.
The semi driver, Clarence F. Jewett Jr., 57, of Galloway, traveled onto the railroad tracks despite active rail grade crossing signals, according to officials.
The oncoming train crashed into the tractor-trailer, causing the tractor-trailer to catch fire.
CSX engineer Jason E. Eiland and the conductor, Daniel A. Peirce, were not injured in the incident.
A railroad worker Rachel Jones, 42, of Sidney, was injured as she was performing maintenance duties alongside of the track.
Jewett was able to climb out of the truck and sustained minor injuries. He was cited for failing to yield to active rail grade signals.
Troopers said alcohol or distracted driving did not contribute to the crash.