HVITC Track Circuit

HVITC Track Circuit

The main function of a track circuit is to detect the presence or absence of traffic on a given railway section of track. High voltage impulse track circuit (HVITC) designed and manufactured by ACTOM Transport, is a comprehensive range of jointed track circuit products, which can be adapted to any kind of track configuration.

An HVITC includes:

  • A transmitter, which generates impulses with a given shape, amplitude and recurrence frequency injected into the tracks by means of a matching isolating transformer
  • A receiver, which detects at the other end of the track section the specific signal and operates the failsafe relay, if the specific signal responds to the correct positive and negative amplitudes.


  • HVITC track circuits are adaptable to these applications
  • Single rail arrangement for a length between 18 m and 750 m
  • The length can be extended to 1 000 m, provided one transmitter per track circuit is used
  • Non-electrified lines
  • DC electrified lines with: 750 V, 1 500V, 3000 V traction
  • AC electrified lines with 25 kV, 50Hz or 60Hz 15kV, 162/3 Hz

Installation conditions:

  • Minimum ballast resistance from 0,6 – 2 ohm/km
  • Drop shunt from 0,15 – 1 ohm
  • Impulse recurrence frequencies: 3 Hz
  • Impulse width: 3 milliseconds
  • Voltage peak value: 100V
  • Current peak value: 100A
  • Standard length of track circuit (with ballast resistance equal to 2 x 2 ohm/km).

HVITC consists of the following basic elements:

  • Power supply: 110V-115VAC 50hz or 60Hz
  • Transmitter: Power 45 VA, 24VDC Voltage limits: +20% – 6%
  • Peak-to-peak max. ripple: 5%
  • Transmitter: 50 W for 24 V equipment
  • The receiver NCO RVT 600 consists of two integrating circuits. The first circuit receives energy from the negative part of the impulse; the second circuit receives energy from the positive part of the waveform.
  • Fail-safe thresholds, and different thresholds eliminate electrical disturbances.

Track relay: NCO CVTH The NCO RVT 600 receiver and NCO CVTH track relay do not require any power. The energy is provided from the track signal.