Identification and Localization of Track Circuit False Occupancy Failures Based on Frequency Domain Reflectometry.

Tiago A Alvarenga,Augusto S Cerqueira,Leonardo M Honorio,Rafael A Nobrega,Luciano M A Filho,Henrique Veloso

doi:10.3390/s20247259

Abstract

Railway track circuit failures can cause significant train delays and economic losses. A crucial point of the railway operation system is the corrective maintenance process. During this operation, the railway lines have the circulation of trains interrupted in the respective sector, where traffic restoration occurs only after completing the maintenance process. Depending on the cause and length of the track circuit, identifying and solving the problem may take a long time. A tool that assists in track circuit fault detection during an inspection adds agility and efficiency in its restoration and cost reduction. This paper presents a new method, based on frequency domain reflectometry, to diagnose and locate false occupancy failures of track circuits. Initially, simulations are performed considering simplified track circuit approximations to demonstrate the operation of the proposed method, where the fault position is estimated by identifying the null points and through non-linear regression on signal amplitude response. A field test is then carried out in a track circuit approximately 1500 m long to validate the proposed method. The results show that the proposed method can identify and estimate the fault location due to a short circuit between rails with high accuracy.

Highlights

The economic demand and the growing necessity to transport goods and people have raised railways’ availability and safety demands
A voltage-controlled oscillator (VCO) for a signal generation; An amplifier, a receiver and a precision rectifier for signal conditioning; An analog to digital converter (ADC); A processing unit composed of a microcontroller or Field Programmable Gate Array (FPGA)
A new method for identification and localization of Track Circuit (TC) false occupancy faults based on reflectometry is proposed

Summary

Introduction

The economic demand and the growing necessity to transport goods and people have raised railways’ availability and safety demands. The most critical component is the signaling and control system, named Track Circuit (TC) [1]. The TC is a series of circuits installed over the railway that measures the shortages between tracks continuity between circuits. It is a device of vast importance, which can be employed to locate trains in a stretch and find track breaks. The most common causes are false occupancy, poor track bed, shortage to the ground or between tracks and broken circuit or track, among others [2]. Any nonconformity in the TC is a critical operational issue and must be investigated and corrected before that specific railway section became functional again. Delays in finding and fixing the problem may disrupt the railway’s services and must be quickly corrected

Methods

Discussion

Conclusion