The tone-frequency microprocessor track circuits MRC-U are designated to monitor occupancy/vacancy of track sections at stations and spans, to monitor integrity of track circuits, to transmit code signals of ALS from wayside devices to a locomotive.

A track circuit power supply module (MPRC) is a combined device containing the following:

• an RC power supply node (a tone-frequency signal generator);
• a two-channel RC monitoring node;
• an ALS code generator node

In the “generator” mode MPRC carries out design of tone-frequency signals and ALS code signals, generating a sum signal of power supply and ALS at the output. In the “receiver” mode, the module carries out simultaneous measurement of levels of two frequency signals and their comparison with a specified setpoint.

A track circuit control module (MKRC) is designated to monitor uncoded branches of track circuits. It contains three independent two-channel RC monitoring (voltage measurement) nodes.

In MPRC and MKRC the same solutions are used as in the object controllers of MPC-U (two diverse channels, operation according to the “2oo2d” scheme).

System advantages

• supplying power, monitoring, and coding track circuits without use of relay equipment;
• parameters of signals of TRC and ALS don’t depend on changes of climatic conditions;
• high noise-immunity of receiving equipment, due to digital filtering;
• continuous diagnostics of receiving-transmitting nodes by means of measurement of parameters of signals being shaped;
• possibility of redundancy of MPRC and MKRC (“hot” redundancy);
• availability of interfaces for coupling with any type of EC;
• resistance to lightning and switching overvoltages;
• use of MRC-U based on digital signal processing assures the following:
• continuous monitoring of cable parameters;
• continuous monitoring of track circuit parameters (including assessment of residual voltage, track circuit integrity, insulation failure of an insulated joint, monitoring of occupancy of diverging branch lines) without additional equipment;
• stable operation of track circuits in case of asymmetry of traction currents up to 50 А, which corresponds to real parameters of asymmetry at railways with the “1520” track;
• absence of necessity of season regulation of track circuit parameters;
• reduction of human factor influence onto rail traffic safety due to a safe function of automated adjustment of track circuit parameters.

NAME

CHARACTERISTICS

   Length of a track circuit

   From 25 m to 1500 m (depends on track line insulation resistance and track circuit configuration)

   Additional shunting zone

   From 0 to 40 m