SIGNALS 7. Employes whose duties may require them to give signals, must provide themselves with the proper appliances, keep them in good order and ready for immediate use. 8. Flags of the prescribed color must be used by day, and lights of the prescribed color by night. 9. Day signals must be displayed from sunrise to sunset, but when day signals cannot be plainly seen, night signals must be used in addition. Night signals must be displayed from sunset to sunrise. Where reference is made in the rules to a red light, a prescribed electric lantern with a prescribed red bulb may be used.