Rail Noise Research Articles

Rail Noise Levels Around Dammam Railway Track and Reported Impacts on Human Health

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On modified wavenumber filters for rail contribution estimations.

This brief communication exposes an overview of various wavenumber filters to separate the rail contribution to pass-by noise via the wave signature extraction method [Zea, Manzari, Squicciarini, Feng, Thompson, and Lopez Arteaga, J. Sound Vib. 409, 24-42 (2017)]. It has been found that the originally proposed filters underestimate the rail noise at frequencies above 1.6 kHz due to the presence of higher-order wave families that is unaccounted for. The goal of this letter is thus to propose and examine different filter functions that can capture such waves, and to assess whether the rail contribution estimations can be improved.

Methods of minimisation of rail-way noise emissions in urban agglomeration

The article presents ways of reducing railway noise in urban agglomeration and analyses noise protection solutions in terms of their effectiveness. In the following part of the article an attempt was made to present typical noise abatement solutions used to reduce rail noise in cities and discuss their advantages and disadvantages.

Derivation of network-wide surface condition corrections for rail noise modelling

Noise modelling and mapping techniques are increasingly being used to understand noise impacts to communities across large geographic areas. Rail transit noise around a network can vary considerably with factors such as track type, train speed, rail roughness/surface condition, among others. Reference source levels for a particular rolling stock type are normally derived by measurement at a particular location or locations, and applied around the network. When modelling noise network wide, it is important to understand how variable rail roughness can affect predicted noise levels at locations other than those used for measurements. With elevated guideway, it can also be difficult to access appropriate external measurement locations. This study describes a study undertaken for the Vancouver SkyTrain network using the Nord2000 rail noise prediction algorithm. Variations in rolling noise level of the order of 15 dB were identified and attributed to rail surface condition. Noise measurements inside a test train were used to determine frequency dependent train speed coefficients and corrections to apply for rail condition around the network. This paper describes the approach used and the outcomes in relation to this city-wide rail noise mapping project.

An Efficient Algorithm for Finding a Threshold of Useful Signals in the Analysis of Magnetic and Eddy Current Defectograms

To ensure traffic safety of railway transport, non-destructive testing of rails is regularly carried out by using various approaches and methods, including magnetic and eddy current flaw detection methods. An automatic analysis of large data sets (defectgrams) that come from the corresponding equipment is still an actual problem. The analysis means a process of determining the presence of defective sections along with identifying structural elements of railway tracks on defectograms. At the same time, under the conditions of significant volumes of incoming information, fast and efficient algorithms of data analysis are of most interest. This article is an addition to the previous article devoted to the problem of automatic determination of a threshold level of amplitudes of useful signals (from defects and structural elements of a railway track) during the analysis of defectograms (records) of magnetic and eddy current flaw detectors, which contains an algorithm for finding the threshold level of a rail noise and its theoretical justification with examples of its operation on several fragments of real magnetic and eddy current defectograms. The article presents a simple and effective implementation of the algorithm, which is successfully used in practice for the automatic analysis of magnetic and eddy current defectograms.

The association of sleep with neighborhood physical and social environment.

While sleep is critical for good health, it remains a major public health concern because millions of individuals do not obtain a sufficient amount of sleep at night to reap proper health benefits. When examining factors that contribute to deleterious sleep outcomes, few researchers to date have examined the physical and social environments together. This article is an analytical essay. In the present study, 18 empirical articles on environmental factors that promote sleep loss were analyzed and synthesized according to the study type, exposure measures, outcome measures, methodology, and findings. Data from the literature demonstrate that neighborhood airplane, roadway, and rail noise pollution; air pollution from ozone and particulate matter (PM10); and, to some extent, ambient light, interfere with residents' ability to fall asleep, stay asleep, and wake feeling rested. There is also some evidence that neighborhood green space, walkability, safety, built environment, and other social characteristics, such as neighborhood disorder and ability to trust one's neighbors, dramatically impact residents' sleep. This article provides a critical assessment of the multidimensional relationship between neighborhood physical and social characteristics and sleep, addresses major methodological concerns that limit current empirical knowledge, and suggests steps to shape future research.

A wavenumber domain numerical analysis of rail noise including the surface impedance of the ground

In most previous studies of sound radiation from railway rails, the rail has been regarded as located in free space, disregarding the influence of the ground. However, in order to predict the noise from the rail more precisely, the effect of the ground should be included in rolling noise predictions. In this study, the rail noise is investigated by means of a wavenumber domain numerical method, including the presence of the ground. For rails attached to a rigid ground or located at a certain distance above it, the influence of the ground is examined in terms of the radiation ratio and longitudinal directivity. From the prediction of radiated power, it is found that the vertical and lateral bending waves of the rail radiate most of the noise for the corresponding direction. Hence, a simplified calculation is proposed that only includes these waves, instead of a full three-dimensional analysis. An absorptive ground is also modelled by applying impedance boundary conditions at the ground surface to investigate the influence of the ground on the rail noise. Finally, for the vertical and lateral bending waves in the rail, the cross-sectional directivity of the noise is predicted for various surface impedances of the ground. It is found that the simplified calculation proposed in this study is valid for the prediction of noise from the rail. Also the presence of the ground and its impedance condition have considerable effects on the level and directivity patterns of the noise radiated from the rail.

Numerical and experimental study on noise reduction of concrete LRT bridges

Rolling noise and structure-borne noise radiating from the bridge are two major sources of noise in light rapid transit (LRT) bridges. To control the noise radiation from LRT bridges, an efficient numerical method for noise prediction is needed. In this study, a combined three-dimensional dynamic model and 2.5-dimensional acoustic model were used to investigate noise reduction in a rail and in a U-shaped girder bridge. The effects of three noise mitigation measures on noise control were then compared: installation of a noise barrier, use of a rail pad with a lower stiffness, and use of a floating ladder track. The corresponding noise reduction was investigated using the numerical method. A field test was conducted to validate the noise reduction effects. It was found that the noise barrier was more effective in reducing the rail noise, and the soft rail pad is more effective to control the bridge noise. The floating ladder track can significantly reduce bridge vibration, but the excessive vibration of the ladder track itself became another major noise source. The findings should guide the selection of appropriate mitigation measures for noise reduction in LRT bridges.

Socioeconomic and ethnic inequalities in exposure to air and noise pollution in London

BackgroundTransport-related air and noise pollution, exposures linked to adverse health outcomes, varies within cities potentially resulting in exposure inequalities. Relatively little is known regarding inequalities in personal exposure to air pollution or transport-related noise. ObjectivesOur objectives were to quantify socioeconomic and ethnic inequalities in London in 1) air pollution exposure at residence compared to personal exposure; and 2) transport-related noise at residence from different sources. MethodsWe used individual-level data from the London Travel Demand Survey (n = 45,079) between 2006 and 2010. We modeled residential (CMAQ-urban) and personal (London Hybrid Exposure Model) particulate matter <2.5 μm and nitrogen dioxide (NO2), road-traffic noise at residence (TRANEX) and identified those within 50 dB noise contours of railways and Heathrow airport. We analyzed relationships between household income, area-level income deprivation and ethnicity with air and noise pollution using quantile and logistic regression. ResultsWe observed inverse patterns in inequalities in air pollution when estimated at residence versus personal exposure with respect to household income (categorical, 8 groups). Compared to the lowest income group (<£10,000), the highest group (>£75,000) had lower residential NO2 (−1.3 (95% CI −2.1, −0.6) μg/m3 in the 95th exposure quantile) but higher personal NO2 exposure (1.9 (95% CI 1.6, 2.3) μg/m3 in the 95th quantile), which was driven largely by transport mode and duration. Inequalities in residential exposure to NO2 with respect to area-level deprivation were larger at lower exposure quantiles (e.g. estimate for NO2 5.1 (95% CI 4.6, 5.5) at quantile 0.15 versus 1.9 (95% CI 1.1, 2.6) at quantile 0.95), reflecting low-deprivation, high residential NO2 areas in the city centre. Air pollution exposure at residence consistently overestimated personal exposure; this overestimation varied with age, household income, and area-level income deprivation. Inequalities in road traffic noise were generally small. In logistic regression models, the odds of living within a 50 dB contour of aircraft noise were highest in individuals with the highest household income, white ethnicity, and with the lowest area-level income deprivation. Odds of living within a 50 dB contour of rail noise were 19% (95% CI 3, 37) higher for black compared to white individuals. ConclusionsSocioeconomic inequalities in air pollution exposure were different for modeled residential versus personal exposure, which has important implications for environmental justice and confounding in epidemiology studies. Exposure misclassification was dependent on several factors related to health, a potential source of bias in epidemiological studies. Quantile regression revealed that socioeconomic and ethnic inequalities in air pollution are often not uniform across the exposure distribution.

WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Effects on Sleep.

To evaluate the quality of available evidence on the effects of environmental noise exposure on sleep a systematic review was conducted. The databases PSYCINFO, PubMed, Science Direct, Scopus, Web of Science and the TNO Repository were searched for non-laboratory studies on the effects of environmental noise on sleep with measured or predicted noise levels and published in or after the year 2000. The quality of the evidence was assessed using GRADE criteria. Seventy four studies predominately conducted between 2000 and 2015 were included in the review. A meta-analysis of surveys linking road, rail, and aircraft noise exposure to self-reports of sleep disturbance was conducted. The odds ratio for the percent highly sleep disturbed for a 10 dB increase in Lnight was significant for aircraft (1.94; 95% CI 1.61–2.3), road (2.13; 95% CI 1.82–2.48), and rail (3.06; 95% CI 2.38–3.93) noise when the question referred to noise, but non-significant for aircraft (1.17; 95% CI 0.54–2.53), road (1.09; 95% CI 0.94–1.27), and rail (1.27; 95% CI 0.89–1.81) noise when the question did not refer to noise. A pooled analysis of polysomnographic studies on the acute effects of transportation noise on sleep was also conducted and the unadjusted odds ratio for the probability of awakening for a 10 dBA increase in the indoor Lmax was significant for aircraft (1.35; 95% CI 1.22–1.50), road (1.36; 95% CI 1.19–1.55), and rail (1.35; 95% CI 1.21–1.52) noise. Due to a limited number of studies and the use of different outcome measures, a narrative review only was conducted for motility, cardiac and blood pressure outcomes, and for children’s sleep. The effect of wind turbine and hospital noise on sleep was also assessed. Based on the available evidence, transportation noise affects objectively measured sleep physiology and subjectively assessed sleep disturbance in adults. For other outcome measures and noise sources the examined evidence was conflicting or only emerging. According to GRADE criteria, the quality of the evidence was moderate for cortical awakenings and self-reported sleep disturbance (for questions that referred to noise) induced by traffic noise, low for motility measures of traffic noise induced sleep disturbance, and very low for all other noise sources and investigated sleep outcomes.

Minimizing noise from metro viaduct railway lines by means of elastic mats and fully closed noise barriers

An adverse effect of urban elevated rail transit systems is the associated noise, which has become a source of environmental complaints. In order to effectively address this problem, an in situ experiment has been conducted on the elevated sections of Hangzhou Metro Line 1 involving three cases: a 2.2 m vertical noise barrier with integrated bed track, a 2.2 m vertical noise barrier with an elastic mat floating slab track, and a 5.1 m fully enclosed noise barrier with an elastic mat floating slab track. The noise reduction effects of the elastic mats and the two kinds of noise barriers for metro viaduct railway lines were evaluated, and the mechanisms of these countermeasures were analysed. The results show that elastic mats can effectively reduce the transmission of wheel–rail vibration energy into the bridge, thus decreasing bridge-borne noise; meanwhile, the elastic mats could lead to an increase in wheel–rail noise. An excellent noise reduction effect was achieved in the area below and near the bottom of the bridge, while an increased noise effect was observed close to the area above and near the rail surface. The fully enclosed noise barrier controlled the propagation of wheel–rail noise more effectively than the vertical noise barriers, but no difference was found between these two kinds of noise barriers in controlling bridge-borne noise.

The Research on Impulsive Events in Railway Noise Generated During Passage Through a Railroad Switch

Abstract This paper presents the result of research on the impulsive components of a railway noise generated during passage through a railroad switch compared with a typical rail noise and evaluation of this phenomenon with particular emphasis on impulsive sounds. The study includes the analysis of the source of impulsive components in the railway noise, the methodology of measurement and data analysis. Spectral analysis of typical fragments passing through a railroad switch is given together with a proposal of additional indicators to assess the noise. Authors propose three descriptors of the impulsive noise such as spectral centroid, kurtosis and impulsiveness, and show that these descriptors can be useful in assessment of the impulsive noise generated during trains’ crossing.

Theoretical investigation into the effect of rail vibration dampers on the dynamical behaviour of a high-speed railway track

Installation of rail vibration dampers (rail dampers for short) onto rails between sleepers is one of the measures to control rail noise generation and roughness growth. Amid the rapid expansion of high-speed and underground railway networks in China, many suppliers are actively marketing and promoting their products, often giving confusing information. In this paper, a parametric study is used to investigate the effect of rail dampers on the dynamical behavior of a Chinese high-speed railway track. The Fourier transform-based method developed for analyzing dynamics of a railway track as an infinitely long periodic structure, with or without rail dampers, is applied in the investigation. It is hoped that results in this paper can help develop the understanding of the working mechanism of rail dampers, and provide useful information for product design and application.

Prediction of rail and bridge noise arising from concrete railway viaducts by using a multilayer rail fastener model and a wavenumber domain method

Concrete viaducts are an important part of urban rail transit systems but they produce considerable noise, thereby affecting the communities living nearby. The vibration generated at the wheel–rail interface is transmitted along the rail and also onto the bridge; hence, noise is radiated from both the rail and the bridge. To facilitate noise prediction, it is desirable to develop a model that takes into account the generation and transmission of vibration in the train–track–bridge system. The vibration and the associated noise of the track–bridge system are computed with a unified vibroacoustic model using a wavenumber domain finite element and boundary element method. An important aspect to note is the frequency-dependent stiffness of a typical rail fastener utilized on bridges due to the resonance of the baseplate between the two rubber pads. In this study, to allow for this effect, a multilayer fastener model is proposed. The proposed procedure is applied to a viaduct with a U-shaped section and compared with field measurements during the passage of trains. The elastic modulus and damping of the rubber pads and the equivalent loss factor of the rail are chosen by fitting the calculated track decay rates to those estimated from the measured rail accelerations under train passages. The wheel–rail combined roughness is also derived from the measured rail vibration. A comparison is then made between the simulated and measured bridge vibration to verify the proposed method as well as the parameters used in the track–bridge system. The predicted noise levels are also compared with the measured results. The effects of the fastener model, fastener stiffness, bridge damping, and interference between multiple wheels are then discussed. It has been found that the bridge noise has a non-negligible effect on the total A-weighted noise levels in the region beneath the bridge and up to 30 m away from the track.

Connected freight rail rolling stock: a modular approach integrating sensors, actors and cyber physical systems for operational advantages and condition based maintenance

For decades, the technology of freight railcars has not changed significantly, mostly due to little or no incentive for significant investments in rolling stock. Taking into account the disruptive developments anticipated in automotive transportation, this approach appears no longer feasible, especially if regulatory agencies aim to reduce carbon dioxide emissions while maintaining economic growth. With the advent of telematics, on-board sensing and cloud-based analytics for control and condition based maintenance, high potential for efficiency improvements has become possible. Such technologies are de facto standards in automotive transport, which induces the need for implementation of similar technologies in rail transport as well. In addition to enabling efficiency gains, telematics, on-board sensing and cloud-based analytics also offer new means to approach pressing problems such as rail noise emission, train integrity and safety against derailment, while at the same time reducing maintenance cost and downtime. Furthermore, a connected wagon offers a seamless integration into current and future logistics systems, which are driven and controlled by the industrial Internet of Things to support the fourth industrial revolution. An important concept, introduced with theWagon 4.0, is standardized hardware, together with an open-source operating system based on prognostics and health management principles for predictive analytics. Thus, the Wagon 4.0 paves the way for new operations and maintenance concepts, user interfaces and value proposals. Additional economic advantages will be made possible from the self-organizing features of such vehicles, the ability to achieve mass customization and from a rise in efficiency in operation and maintenance. This paper describes the basis of such a system including the power supply, intra-train communications, sensing and cloud-based analytics. A study of use cases from railway operation illustrates the approach and highlights the opportunities of this novel system design. The paper concludes with a description of how the implantation enables the railcar operator to practice predictive maintenance and increase operational efficiency.

Environmental Ground-Borne Noise and Vibration from Urban Light Rail Transportation During Construction and Operation

Environmental vibration and ground-borne noise from light rail transport (LRT) networks consists a major impact on the urban environment. Since experiments are often difficult to obtain and to interpret especially for environmental vibration, designers and researchers generally resource numerical model to assess vibration levels and understand the complex mechanism of generation and propagation of ground vibration. In this paper, some highlights are provided on vehicle/track/soil modeling for railway-induced ground vibration, including the proper definitions of each of these subsystems. The nature of the wheel/rail interaction is also important, especially in urban area, so a case study demonstrates that local unevenness are important sources of vibrations. On the other hand, specialized prediction models and dose-response relationships for airborne rail noise during operation and construction phases of urban light rail transport networks (both underground and surficial) are needed to be evaluated, in order to quantify the impact of the technical characteristics of the noise source, the operation mode with emphasis to speed, the propagation, the implementation of quiet facades, and the number and distribution of high-level noise events. In the present paper, two distinct case studies are presented in order to emphasize the need and the necessity of using proper tools to predict, access, monitor, and evaluate the environmental impact of LRTs to the urban acoustic environment: (a) the new Brussels Regional Express Network and (b) the new Athens Metro Line 3 extension to Piraeus port in an underground tunnel (length 7.6 km).

Analysis of the active control of steering bogies for the dynamic characteristics on real track conditions

In this study, an active steering bogie with a re-designed primary axial rubber spring for urban trains was developed. The applied axial rubber spring had a reasonable stiffness that can be achieved in the X, Y and Z directions. Therefore, the steering performance of the bogie can improve because of the lower longitudinal stiffness. The running performance of an active steering vehicle on a curved track was simulated by means of a co-simulation with VI-Rail and MATLAB/Simulink. Further, a control algorithm was developed and applied to an actual active steering bogie. The radius of curvature acquired from the actual active steering bogie by the control algorithm was in reasonable agreement with that acquired from a track inspection vehicle. The numerical analysis revealed a significant improvement in the vehicle safety and ride quality and a reduction in the wheel–rail wear and noise. As a result, the validities of the developed primary suspension and control algorithm of the active steering bogie were confirmed. Further, this study may enable railway vehicles to run more stably and faster on sharp curves.

On Finding a Threshold of Useful Signals in the Analysis of Magnetic and Eddy Current Defectograms

To ensure traffic safety of railway transport, non-destructive testing of rails is regularly carried out by using various approaches and methods, including magnetic and eddy current flaw detection methods. The paper is devoted to the problem of automatic determination of a threshold level of amplitudes of useful signals (from defects and structural elements of a railway track) during the analysis of defectograms (records) of magnetic and eddy current flaw detectors. A signal is considered useful (and is subject to further analysis) if a deviation of its value from an average of all signals is at least twice the threshold noise level of rails. The probability of obtaining a signal from a section without structural elements (a rail noise signal) is characterized by the normal distribution law. Thus, the rule of three sigma can be used to calculate the threshold noise level. And a signal is useful if its amplitude deviation from a sample mean exceeds twice the threshold noise level. The paper proposes an algorithm for finding the threshold level of a rail noise and gives its theoretical justification, and it also examines examples of its operation on several fragments of real magnetic and eddy current defectograms.

A Health-Based Metric for Evaluating the Effectiveness of Noise Barrier Mitigation Associated With Transport Infrastructure Noise.

Introduction:This study examines the use of the number of night-time sleep disturbances as a health-based metric to assess the cost effectiveness of rail noise mitigation strategies for situations, wherein high-intensity noises dominate such as freight train pass-bys and wheel squeal.Materials and Methods:Twenty residential properties adjacent to the existing and proposed rail tracks in a noise catchment area of the Epping to Thornleigh Third Track project were used as a case study. Awakening probabilities were calculated for individual’s awakening 1, 3 and 5 times a night when subjected to 10 independent freight train pass-by noise events using internal maximum sound pressure levels (LAFmax).Results:Awakenings were predicted using a random intercept multivariate logistic regression model. With source mitigation in place, the majority of the residents were still predicted to be awoken at least once per night (median 88.0%), although substantial reductions in the median probabilities of awakening three and five times per night from 50.9 to 29.4% and 9.2 to 2.7%, respectively, were predicted. This resulted in a cost-effective estimate of 7.6–8.8 less people being awoken at least three times per night per A$1 million spent on noise barriers.Conclusion:The study demonstrates that an easily understood metric can be readily used to assist making decisions related to noise mitigation for large-scale transport projects.

Noise and Vibration Emissions of Railway Bridges

The goal of the paper is to address the problem of ground Bourne vibration and ways in which both humans and railway bridge structures respond to it. The methods of reducing the vibration and noise caused to railways bridges have been discussed. Transportation noise is one of the main components of environmental noise. It is estimated that around 1.7% of the total noise caused in the environment is due to the rail noise. Mainly the source of noise and vibration emissions of railway lines is due to the rough contact area of the wheel-rail, the time when a train is travelling on a bridge. Vibration is transmitted from the rail to the bridge via the track support structure. As of now, there is only little knowledge about the noise emission from railway bridges. The recent finding on the causes and reduction of these noise and vibration in bridges has been presented here.