Sec. 39. Whenever a person who drives a vehicle approaches a railroad grade crossing, the person shall stop within fifty (50) feet but not less than fifteen (15) feet from the nearest track of the railroad and may not proceed until the person can do so safely under the following circumstances:
(1) When a clearly visible electric or mechanical signal device gives warning of the immediate approach of a train or other on-track equipment.
(2) When a crossing gate is lowered or when a human flagman gives or continues to give a signal of the approach or passage of a train or other on-track equipment.
(3) When a railroad train or other on-track equipment approaching within one thousand five hundred (1,500) feet of a highway crossing emits an audible signal and because of speed or nearness to the crossing is an immediate hazard.
(4) When an approaching train or other on-track equipment is plainly visible and is in hazardous proximity to the crossing.