SIGNAL LIGHT MEANS COMPRISING AN ELONGATE HOLLOW MOUNTING BAR; A PAIR OF SIGNAL LIGHTS MOUNTED ADJACENT THE OPPOSITE ENDS OF SAID BAR; EACH LIGHT COMPRISING A BASE, A LIGHT TRANSMITTING DOME ON THE BASE, A SHAFT JOURNALLED ON THE BASE AND EXTENDING UPWARDLY INTO THE DOME AND DOWNWARDLY INTO SAID BAR, LAMP MEANS ON THE UPPER END PORTION OF SAID SHAFT WITHIN SAID DOME, AND SPROCKET MEANS ON THE LOWER END PORTION OF SAID SHAFT WITHIN SAID BAR; A MOTOR IN ONE OF SAID LIGHTS DRIVINGLY CONNECTED TO THE SHAFT THEREIN; A PARTITION WITHIN SAID BAR IMMEDIATELY BELOW AND EXTENDING BETWEEN SAID SPROCKET MEANS; CHAIN MEANS IN SAID BAR ABOVE SAID PARTITION REAVED OVER SAID SPROCKET MEANS FOR IMPARTING THE MOVEMENTS OF THE MOTOR DRIVEN SHAFT TO THE OTHER OF SAID SHAFTS; SAID BAR FITTING CLOSELY ABOUT SAID SPROCKET MEANS WHEREBY SAID BAR AND SAID PARTITION PREVENT DISASSOCIATION OF SAID CHAIN MEANS FROM SAID SPROCKET MEANS; AND POWER SUPPLY MEANS FOR SAID LAMP MEANS AND SAID MOTOR EXTENDING THROUGH SAID BAR BELOW SAID PARTITION.