Railway Track Condition Assessment at Network Level by Frequency Domain Analysis of GPR Data

Abstract

Abstract:The railway track system is a crucial infrastructure for the transportation of people and goods in modern societies. With the increase in railway traffic, the availability of the track for monitoring and maintenance purposes is becoming significantly reduced. Therefore, continuous non-destructive monitoring tools for track diagnoses take on even greater importance. In this context, Ground Penetrating Radar (GPR) technique results yield valuable information on track condition, mainly in the identification of the degradation of its physical and mechanical characteristics caused by subsurface malfunctions. Nevertheless, the application of GPR to assess the ballast condition is a challenging task because the material electromagnetic properties are sensitive to both the ballast grading and water content. This work presents a novel approach, fast and practical for surveying and analysing long sections of transport infrastructure, based mainly on expedite frequency domain analysis of the GPR signal. Examples are presented with the identification of track events, ballast interventions and potential locations of malfunctions. The approach, developed to identify changes in the track infrastructure, allows for a user-friendly visualisation of the track condition, even for GPR non-professionals such as railways engineers, and may further be used to correlate with track geometric parameters. It aims to automatically detect sudden variations in the GPR signals, obtained with successive surveys over long stretches of railway lines, thus providing valuable information in asset management activities of infrastructure managers.

Non-destructive Assessment and Health Monitoring of Railway Infrastructures

“…Various NDT methods have been reported to date for use on assessment and health monitoring of railway tracks (Clark et al 2004;Narayanan et al 2004;Eriksen et al 2006;De Bold 2011;Donohue et al 2011;Fumeo et al 2015;Benedetto and Pajewski 2015;Fontul et al 2016Fontul et al , 2018. Throughout this paper, main techniques for inspection of the structural components of a railway track are reported.…”

A Review of GPR Application on Transport Infrastructures: Troubleshooting and Best Practices

“…Not only are the antennas different, but the signal processing is also distinct, according to the purpose of the measurement. Although the reflection picking method is sufficient for layer thickness assessment, in the case of moisture and fouling evaluation, more complex signal processing is required, such as signal scattering [281] and the time-frequency approach [93,282,283]. This also requires different antenna configuration [284] and testing methodology, such as the CMP approach [279].…”

Future Trends in Transport Infrastructure Monitoring

“…It was applied at research level for detecting damage in airport pavements, using ground coupled antennas [7]. The application of this approach to the assessment of railway infrastructure is presented in this study as an example of possible infrastructure monitoring at the network level [8]. The measurements were performed with a 400 GHz air coupled antenna.…”

“…where: a and A are the GPR signal amplitudes in the time and frequency domains, respectively; subscripts S and L denote the short and long sliding windows and m denotes the averaged signal in the specified window; t 1 and t 2 are the lower (7 ns Figure 5 in terms of the mean or averaged signal (denoted by subscript m) over the shorter (a S,m and A S,m ) or longer (a L,m and (a L,m ) sliding windows; percentiles 5% and 95% of the longer window are also plotted to illustrate the variability of the signal [8].…”