Railroad globe lanterns

At the turn of the 20th century, railroad operators used colored globe lanterns for illumination and signaling at night. The meanings of the colors were the precursors to our modern traffic light system.

White was used to indicate that it was safe to proceed, green signaled caution, and red meant stop or danger. As more people in towns and cities began using white light for general illumination, the use of the white lantern became difficult to see. The railroads switched to using green for "proceed" and introduced yellow or orange as the "caution" color.