Equipment device for railway tracks

摘要

The central block has a circuit (42) which couples with right or left blocks (48,47) at first and second frequencies (F1,F2) and coupling circuits (43,45) linked to the transmitter and receiver (44,46). At the first frequency the right block is short circuited and the left block open circuited and at the second frequency the converse applies such that the joint is respectively a receiver and transmitter at the two frequencies. <??>An Independent claim is also included for a method for detecting the passage of a train using a three block joint and frequencies between 20 and 100KHz.