Abstract: A safety device for a transport system in which a vehicle travels on a track divided into sequential sections operates to stop the vehicle when a parameter representing the motion of the vehicle exceeds a threshold in the course of travelling over a track section. The device comprises two comparators each delivering during passage of the vehicle in each track section a comparison signal having a first value when the parameter remains within the threshold and a second value when the parameter exceeds the threshold. A coincidence detector is connected to receive the output signals of the two comparators and operates to initiate emergency braking of the vehicle if the output signals of the two comparators do not simultaneously have the same value during travel in a track section.

Abstract: A device for checking the insulation of the leads connecting a power generator to a receiver. The receiver is sensitive to d.c. signals having an amplitude above a given threshold. A first output of an interference generator is connected to the first lead via a current detector and a resistor. A second output of the interference generator is connected to the second lead via a checking generator transmitting a.c. signals and a resistor. The current detector is sensitive only to a.c. signals transmitted by the checking generator.