Dynamic Modelling and Acceleration Signal Analysis of Rail Surface Defects for Enhanced Rail Condition Monitoring and Diagnosis

Early detection of rail surface defects (RSDs) is crucial for timely rail maintenance, repair, or replacement to prevent potential risk of rail breaks and train derailments. Axle box acceleration (ABA) measurement is commonly used to identify rail and track irregularities. This paper aims to (1) model and simulate three common RSDs (rail corrugation, spalling, and squat) with three severity levels (light, moderate, and severe); (2) process and analyse simulated RSD-driven ABA signals; and (3) ascertain relationships between RSDs and their corresponding ABA signals. Explicit dynamic finite element models of wheel-rail interaction were created for rails with and without RSDs. Simulated RSD-driven ABA signals were subsequently processed and analysed using various signal processing algorithms including short-time Fourier transform, continuous wavelet transform, empirical mode decomposition, and power spectral density. Results reveal the likelihood of automatically detecting and classifying different types and different severity levels of RSDs from ABA signals, thereby enhancing the efficiency and effectiveness of rail condition monitoring and diagnosis.

I. Introduction

Rail is a key component of a railway track; it supports and guides the trains that carry people, animals, and goods from one place to another. As the contact area between wheel and rail is small, rail surface is constantly subjected to high contact pressure. Rail surface defects (RSDs) are consequently developed due to fluctuation of wheel-rail contact pressure, rolling contact fatigue, as well as rail bending, thermal, and residual stresses [1]. RSDs elevate wheel-rail contact pressure and augment vehicle-track vibration and noise level, creating an unsafe and unpleasant commute. According to their appearances, RSDs can be broadly categorised into two groups: rail corrugation and rail contact fatigue defects [1]. Rail corrugation has a quasi-periodic wear pattern, whereas rail contact fatigue defects, for instance, flaking, spalling, squats, and shelling, have no repeating patterns.