Project Description

Non-Isolated Audible Frequency (AF) Track Circuit Device

It is a non-insulated track circuit device designed for AC or DC train section where there is electromagnetic interference (mainly generated from the harmonic wave of the electric line power supply). It detects the presence/absence of the train, does not carry a speed code.

Pre-Nonpolar Line Relay

Pre-Nonpolar Line Relay

Product Information

The track relay of the AF track circuit accepts the output voltage of the sending module from the receiving module, and if the input signal exceeds a certain value, the relay output voltage is generated to operate the relay.
In addition, if the input signal is smaller than a certain value, the relay output voltage is not generated and the relay is not driven. The track circuit relay is based on the railway standard KRS SG 0005 (non-polar line relay).

Online Inquiry


  • Detecting the presence of trains to prevent accidents
  • Achieve safe operation of trains by communicating the train speed and vehicle operation information to the locomotive


  • Non-polar relay contact; – 4NR, 4N, 2R
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