TRACK CIRCUIT Russian patent published in 2005 - IPC

FIELD: railway signaling and communication.

SUBSTANCE: invention relates to tone track circuits with adjustable sensitivity of track receiver. Proposed track circuit contains track generators and rail lines. Each rail line has matching element, limiting resistor, band-pass filter and track receiver. The latter is furnished with rectifier, smoothing filter, analog-digital converter, register, clock-pulse generator, AND gates, diode, capacitor, resistor, OR gates, temperature pickup, moisture pickup, programmable read-only memory and multiplexer. Output of first generator is connected with one end of first rail line through first resistor and first matching element. Inputs of first and second band-pass filters are connected to other end of first rail line through second matching element and second resistor. Output of first filter is connected with analog input of first receiver, and output of second filter is connected with analog input of second receiver. Output of second generator is connected with supply ends of second and third rail lines through third resistor and third matching element. Input of third and fourth band-pass filters are connected to second end of third rail line through matching element and fourth resistor. Output of each filter is connected to analog input of third and fourth receivers, respectively. Output of each receiver is connected with first input of receiver of following track circuit and with second input of receiver of preceding track circuit. Analog input of each receiver is connected with input of rectifier. Output of rectifier is connected through smoothing filter with input of analog-digital converter whose outputs are connected with information inputs of register and first inputs of multiplexer. Second inputs of multiplexer are connected with outputs of programmable read-only memory whose first inputs are connected with outputs of register, and second inputs, with outputs of OR gate. First inputs of first and second OR gates are connected with temperature pickup, and first inputs of third and fourth OR gates, with moisture pickup. Second inputs of all OR fates are connected through capacitor and resistor with minus terminal of supply source and, through diode, with first input of first AND gate and with output of second AND gate. Two inputs of second AND gate are connected with inputs of receiver coupled with receivers of adjacent rail lines, and second input, with outputs of multiplexer and receiver. Second input of first AND gate is connected with output of clock-pulse generator. Track section clear check is provided by comparing current voltage of receiving end of track circuit with voltage across said end before train enters the track section with due account of correction to ballast drying.

EFFECT: improved reliability of checking condition of track sections at reduction of insulation resistance when said section or adjacent section is occupied.

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