Coded Current

Coded Current Automatic Block - BACC

System measures the magnetic field produced by the coded rail currents and analyzes their signal and modulation looking for anomalies of both current source and detectors.

BACC is a train protection system used in Italy on railway lines using 3kV DC electrification (mainline and regional lines). The term is an abbreviation of Blocco Automatico a Correnti Codificate (Coded Current Automatic Block).
BACC is a simple cab signalling system that requires the driver to acknowledge any change in the aspect of the next signal, continuously monitors the train speed, and computes braking curves according to the train's length, mass, and braking ability.

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Coded Current Automatic Block - BACC

The information is conveyed by superposition of two amplitude-modulated alternating currents in the rails (with a carrier frequency of 50 Hz and 178 Hz, respectively). Receiver coils in front of the first axle of a locomotive or control car are used to detect the signal.

MERMEC monitoring system measures the magnetic field produced by the coded rail currents and analyzes their signal and modulation looking for anomalies of both current source and detectors. Dedicated sensors are installed in front of the first axle of a locomotive or control car in both vehicle directions.

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Acquired Parameters
  • Signal amplitude from right and left sensors
  • Electro-magnetic field intensity
Calculated Parameters
  • Spectrum
  • Carriers Frequency
  • Carriers Intensity
  • Carriers Alerts
  • Code division
  • Carriers Intensity for track circuits
  • RMS index
  • Return currents asymmetry
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Served Railways
Mass TransitMass Transit
Main & RegionalMain & Regional

 
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