FIELD: railway transport; switch automatic control. SUBSTANCE: device has self-excited oscillator and pulse shaper for exciting damped harmonic oscillation in parallel circuits formed by pickup coils and circuit capacitors. Damped oscillations are converted by circuit into check pulses which are compared with reference pulses by special circuit acting on actuating relay basing on results of comparison. Pickups are installed in stock rail necks opposite to tongue surfaces between fastening members of drive operating tie-rod. Oscillations damping time in circuits is proportional to distance between pickups and tongue surface within checked values range. EFFECT: improved safety of railway traffic. 3 cl, 3 dwg
