Abstract: An electrical joint for separating adjacent block circuits of a railway signaling system in which the rails of the railway track serve as conductors. The upstream circuit block carries first frequency signals and the downstream block circuit carries second frequency signals. The electrical block separating joints are bounded by tuning units of which one may be a mere impedance and which are responsive to the frequencies of the circuit blocks and constitute respectively a low impedance for the first or second frequency and a capacitive impedance for the other of the first or second frequency. There are transmitter and receiver units the latter of which is associated to activate a control device, e.g. a relay, for the associated block circuit to de-activate the control device when a vehicle enters the electrical joint by a shunting effect.