Train wheel proximity detector

Claim 1

A TRAIN WHEEL PROXIMITY DETECTOR FOR RIGID MOUNTING TO A TRACK RAIL TO INDIVIDUALLY DETECT EACH SUCCESSIVE TRAIN WHEEL TRANSVERSING SUCH RAIL AND COMPRISING AN OSCILLATOR CIRCUIT THAT INCLUDES A DETECTOR PLATE HAVING A CAPACITANCE EFFECT IN SAID CIRCUIT DETERMINING A STABLE FREQUENCY OF OSCILLATION THEREOF, MEANS MOUNTING SAID DETECTOR PLATE IN INSULATED SPACED RELATION ALONG THE GAUGE SIDE OF THE RAIL, WITH SAID PLATE BEING DISPOSED TO EXTEND IN A PREDOMINANTLY HORIZONTAL PLANE LOCATED IN VERTICALLY SPACED RELATION BENEATH THE FLANGE PATH OF EACH TRAIN WHEEL TRAVERSING THE RAIL SUCH THAT UPON THE APPROACH AND MOVEMENT OF A TRAIN WHEEL THEREOVER, THE CAPACITANCE EFFECT OF SAID DETECTOR PLATE IN SAID OSCILLATOR CIRCUIT MOMENTARILY INCREASES TO MOMENTARILY TERMINATE OSCILLATION OF SAID CIRCUIT AT SAID STABLE FREQUENCY, CONTROL MEANS RESPONSIVE EACH TIME SAID OSCILLATOR CIRCUIT TERMINATES ITS OSCILLATION AT SAID STABLE FREQUENCY, AND UTILIZATION MEANS CONNECTED FOR ACTUATION BY EACH SUCH RESPONSE OF SAID CONTROL MEANS.