Counter-turn and Pass-Off Devices:There is a structural dependency between the exit flags of two adjacent stations that allow the passage of a forward pass signal at the same track of one station at a time, and the passage passage is repeated with the previous pass upon arrival at the other host may appearVigilance control:the control of the driving behavior of a towing vehicle in the event of a loose signaling by means of the road or time proportional to the activities required in some cases.Semi-Self-Hazard Beacon:Drive-by Signal Displays Under the Effect of a Train in Progress and Drive-Enable Discharge Signal Displays.