Technical Reports

Inductive Interference in Rapid Transit Signaling Systems, Volume I: Theory and Background

  • 01
  • May
  • 1986
AUTHOR: F. Ross Holmstrom
SUBJECT: Signal and Train Control
KEYWORDS: Automatic Train Control Systems, Chopper-Controlled Propulsion Systems, Audio-Frequency Signaling Systems
ABSTRACT: This report analyzes the problem of inductive interference with audio-frequency signaling caused by chopper-controlled propulsion systems on rapid transit vehicles. After discussing audio-frequency track circuits, the report examines chopper interference generation as well as methods for observing and recording interference signals. The report develops a physical model for calculating levels of inductive interference, gives selected results of field observations, and discusses methods for alleviating the problem, such as improved track signal detection, frequency-domain coding, and new chopper components that generate less stray flux.