Indiana Code Title 9. Motor Vehicles § 9-21-8-39

(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.