A system on a railroad hopper car for providing an indication, observable by a person located either proximate to or remote from the hopper car, of a condition of a lock arranged in operable combination with a mechanism on the hopper car for controlling discharge of material from the hopper car. The system includes electric circuitry and a sensor for providing a signal when each discharge mechanism lock on the railcar is in the locked condition and for producing another signal when each discharge mechanism lock on the railcar is in the unlocked condition. An illuminable indicator, mountable on a side of the railroad hopper car, is responsive to signals from the circuitry for displaying the condition of the discharge mechanism locks. A method for visually displaying a condition of a lock on a railroad hopper car as through use of illumination is also disclosed.