Overview

Audio Frequency Track Circuit

General

The non-isolated AF track circuit is designed to detect trains and to transmit information between the on-board device and the track-side devices. The AF track circuit is composed of a transmitter module, a receiver module, a monitoring module, a power module and a tuning unit, and its function is enhanced when combined with TLDS (Track Circuit Level Detector System).

Related Standard

▪ KRS SG 0033-18R

▪ KRS SG 0038-18R

Features

  • ▪ nsulated rail joints are not required
  • ▪ Quality of train ride will be improved
  • ▪ Maintenance cost can be reduced
  • ▪ Audio Frequency Track Circuit Equipment can be installed regardless of the curves and gradients of tracks
  • ▪ The length of Audio Frequency Track Circuit is limited within the range from 50 meters to 1,000 meters at 0.5~0.1 mho/km of leakage conductance
  • ▪ The shunting sensitivity of track : 0.1Ω ~ 1.7Ω
  • ▪ The ambient temperature : -40℃~+70℃

Specifications

Classification Item Specification
Transmitter/Receiver
Module Sub-Rack		 Power module Input voltage: AC 110V/220V
Output voltage : 24VDC/8A
Transmitter module Rated voltage : 24VDC
Operating voltage : 22.5VDC ~ 30.5VDC
Power consumption: 2.2A or less
Output : 3 ~ 40 W
Receiver module Rated voltage : 24VDC
Operating voltage : 22.5VDC ~ 30.5VDC
Power consumption : 1A or less
Relay drive output voltage : 24VDC±2V
Tuning Unit General type For isolation from adjacent track circuits.
Termination type
Compatibility B2 For the return current to the substation.
AC 60Hz, 1,000A



Frequency
Track 1 A 1699Hz B 2296Hz
Track 2 C 1996Hz D 2593Hz
Track 3 E 1549Hz F 2146Hz
Track 4 G 1848Hz H 2445Hz

System structure