In recent years, the range of sensing technologies has expanded rapidly, whereas sensor devices have become cheaper. This has led to a rapid expansion in condition monitoring of systems, structures, vehicles, and machinery using sensors. Key factors are the recent advances in networking technologies such as wireless communication and mobile ad hoc networking coupled with the technology to integrate devices. Wireless sensor networks (WSNs) can be used for monitoring the railway infrastructure such as bridges, rail tracks, track beds, and track equipment along with vehicle health monitoring such as chassis, bogies, wheels, and wagons. Condition monitoring reduces human inspection requirements through automated monitoring, reduces maintenance through detecting faults before they escalate, and improves safety and reliability. This is vital for the development, upgrading, and expansion of railway networks. This paper surveys these wireless sensors network technology for monitoring in the railway industry for analyzing systems, structures, vehicles, and machinery. This paper focuses on practical engineering solutions, principally, which sensor devices are used and what they are used for; and the identification of sensor configurations and network topologies. It identifies their respective motivations and distinguishes their advantages and disadvantages in a comparative review.

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Wireless Sensor Networks for Condition Monitoring in the Railway Industry: A Survey

The recent surge in using wearable personalized devices has made it increasingly important to have flexible textile-based sensor alternatives that can be comfortably worn and can sense a wide range of body strains. Typically fabricated from rigid materials such as metals or semiconductors, conventional strain sensors can only withstand small strains and result in bulky, inflexible, and hard-to-wear devices. Textile strain sensors offer a new generation of devices that combine strain sensing functionality with wearability and high stretchability. In this review, we discuss recent exciting advances in the fabrication, performance enhancement, and applications of wearable textile strain sensors. We describe conventional and novel approaches to achieve textile strain sensors such as coating, conducting elastomeric fiber spinning, wrapping, coiling, coaxial fiber processing, and knitting. We also discuss how important performance parameters such as electrical conductivity, mechanical properties, sensitivity, sensing range, and stability are influenced by fabrication strategies to illustrate their effects on the sensing mechanism of textile sensors. We summarize the potential applications of textile sensors in structural health monitoring, wearable body movement measurements, data gloves, and entertainment. Finally, we present the challenges and opportunities that exist to date in order to provide meaningful guidelines and directions for future research.

Textile Strain Sensors: A Review of the Fabrication Technologies, Performance Evaluation and Applications

This paper is a review of the effect of vehicle characteristics on ground- and track borne-vibrations from railways. It combines traditional theory with modern thinking and uses a range of numerical analysis and experimental results to provide a broad analysis of the subject area. First, the effect of different train types on vibration propagation is investigated. Then, despite not being the focus of this work, numerical approaches to vibration propagation modelling within the track and soil are briefly touched upon. Next an in-depth discussion is presented related to the evolution of numerical models, with analysis of the suitability of various modelling approaches for analysing vehicle effects. The differences between quasi-static and dynamic characteristics are also discussed with insights into defects such as wheel/rail irregularities. Additionally, as an appendix, a modest database of train types are presented along with detailed information related to their physical attributes. It is hoped that this information may provide assistance to future researchers attempting to simulate railway vehicle vibrations. It is concluded that train type and the contact conditions at the wheel/rail interface can be influential in the generation of vibration. Therefore, where possible, when using numerical approach, the vehicle should be modelled in detail. Additionally, it was found that there are a wide variety of modelling approaches capable of simulating train types effects. If non-linear behaviour needs to be included in the model, then time domain simulations are preferable, however if the system can be assumed linear then frequency domain simulations are suitable due to their reduced computational demand.

https://www.tandfonline.com/doi/pdf/10.1080/23248378.2014.897791

Railway-induced ground vibrations – a review of vehicle effects

Benchmarking railway vibrations – Track, vehicle, ground and building effects

Traditionally, damage identification techniques in bridges have focused on monitoring changes to modal-based Damage Sensitive Features (DSFs) due to their direct relationship with structural stiffness and their spatial information content. However, their progression to real-world applications has not been without its challenges and shortcomings, mainly stemming from: (1) environmental and operational variations; (2) inefficient utilization of machine learning algorithms for damage detection; and (3) a general over-reliance on modal-based DSFs alone. The present paper provides an in-depth review of the development of modal-based DSFs and a synopsis of the challenges they face. The paper then sets out to addresses the highlighted challenges in terms of published advancements and alternatives from recent literature.

https://www.mdpi.com/2076-3417/7/5/510/pdf

A State of the Art Review of Modal-Based Damage Detection in Bridges: Development, Challenges, and Solutions

Wayside detection monitors critical parameters relating to the condition of in-service railway vehicles. Economic decisions about the maintenance of vehicles can be made, and servicing can occur wh...

Structural Health Monitoring in the Railway Industry: A Review:

Out-of-round rollingstock wheels are caused by skidding or spalling of the wheel tread and by dynamic motion of wheels and wheelsets in service. Out-of-round wheels generate impact forces at the wheel-rail interface, which are transferred to train and to track components including rail and both bolted and welded rail joints, prestressed concrete sleepers, ballast, wheels, and bearings.To make a rational decision about removing out-of-round wheels from service, estimation of the damage caused by an individual wheel is required. Previous studies have used analytical and numerical models to illustrate the distribution of impact into track and rolling stock components. These models are compared here. The review details mathematical models and studies of the lives of the earlier-listed components, which would provide a means of determining the damage caused by impacting wheels. In addition, studies have found that impacting wheels increase fuel consumption and increase pass-by noise levels, which are a...

A Review of the Effects of Out-of-Round Wheels on Track and Vehicle Components

Transient stress waves have been used to quantify the extent of damage in cylindrical structures. In the present study, this technique is extended to the in situ quantification of damage in a bolt. Piezoelectric wafers were bonded to either end of two bolts, one of which was loaded in tension in a steel block. Both bolts were incrementally damaged by sawing a cut, to observe the changes in a stress wave which had traversed the bolts in the presence of increasing damage. A clear relationship between the extent of damage in the bolt and the attenuation of the stress wave was observed. Tension in the bolt did not affect this relationship, illustrating the in situ applicability of the technique.In a second set of experiments, bolts were subjected to conditions in which stress corrosion cracking would occur, whilst stress waves were excited in each bolt, to illustrate the ability of the method to detect a naturally occurring form of damage. It was found that the attenuation of a stress wave which had traversed...

Derek Woolrich Barke

Papers

Structural Health Monitoring in the Railway Industry: A Review:

A Review of the Effects of Out-of-Round Wheels on Track and Vehicle Components

In situ Damage Quantification in Bolts

Damage detection in bolts under service load by stress wave attenuation