| 摘要 |
A railway safety system uses intensity of current measurements in order that a train driver can have a continuous evaluation of the mutual distance between his train and the next one in front of or rear to it. Two ammeters give this indication by measuring the current intensity in the corresponding circuit encompassed on a resistive line parallel to the railroad, by the associate sliding contacts on both trains, since each train is provided with a pair of pantographs in contact with said resistive line and a generator of d.c. which thus flows in the circuit closed by two trains and comprising the half circuit in series with the concerned pantograph of each train and the intermediate length of resistive line. A reverser relay applies the voltage of the generator to either of the two half circuits of a train. Switch relays may be provided to operate acoustic signals and/or the automatic braking device at given values of the flowing current. Examples of how to calculate the resistance values of the half circuits and resistive line are given, according to the prefixed value of safety distance, the position of the pantographs and the possibility of frontal collisions in single-track railroads.
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