Rail roughness and rolling noise in tramways

Companies which manage railway networks have to cope continually with the problem of operating safety and maintenance intervention issues related to rail surface irregularities. A lot of experience has been gained in recent years in railway applications but the case of tramways is quite different; in this field there are no specific criteria to define any intervention on rail surface restoration. This paper shows measurements carried out on some stretches of a tram network with the CAT equipment (Corrugation Analysis Trolley) for the principal purpose of detecting different states of degradation of the rails and identifying a level of deterioration to be associated with the need for maintenance through rail grinding. The measured roughness is used as an input parameter into prediction models for both rolling noise and ground vibration to show the potential effect that high levels of roughness can have in urban environment. Rolling noise predictions are also compared with noise measurements to illustrate the applicability of the modelling approach. Particular attention is given to the way the contact filter needs to be modelled in the specific case of trams that generally operate at low speed. Finally an empirical approach to assess vibration levels in buildings is presented

Integrating spatial and temporal approaches for explaining bicycle crashes in high-risk areas in Antwerp (Belgium)

The majority of bicycle crash studies aim at determining risk factors and estimating crash risks by employing statistics. Accordingly, the goal of this paper is to evaluate bicycle-motor vehicle crashes by using spatial and temporal approaches to statistical data. The spatial approach (a weighted kernel density estimation approach) preliminarily estimates crash risks at the macro level, thereby avoiding the expensive work of collecting traffic counts; meanwhile, the temporal approach (negative binomial regression approach) focuses on crash data that occurred on urban arterials and includes traffic exposure at the micro level. The crash risk and risk factors of arterial roads associated with bicycle facilities and road environments were assessed using a database built from field surveys and five government agencies. This study analysed 4120 geocoded bicycle crashes in the city of Antwerp (CA, Belgium). The data sets covered five years (2014 to 2018), including all bicycle-motorized vehicle (BMV) crashes from police reports. Urban arterials were highlighted as high-risk areas through the spatial approach. This was as expected given that, due to heavy traffic and limited road space, bicycle facilities on arterial roads face many design problems. Through spatial and temporal approaches, the environmental characteristics of bicycle crashes on arterial roads were analysed at the micro level. Finally, this paper provides an insight that can be used by both the geography and transport fields to improve cycling safety on urban arterial roads

Using natural means to reduce surface transport noise during propagation outdoors

This paper reviews ways of reducing surface transport noise by natural means. The noise abatement solutions of interest can be easily (visually) incorporated in the landscape or help with greening the (sub)urban environment. They include vegetated surfaces (applied to faces or tops of noise walls and on building façades and roofs ), caged piles of stones (gabions), vegetation belts (tree belts, shrub zones and hedges), earth berms and various ways of exploiting ground-surface-related effects. The ideas presented in this overview have been tested in the laboratory and/or numerically evaluated in order to assess or enhance the noise abatement they could provide. Some in-situ experiments are discussed as well. When well-designed, such natural devices have the potential to abate surface transport noise, possibly by complementing and sometimes improving common (non-green) noise reducing devices or measures. Their applicability strongly depends on the available space reserved for the noise abatement and the receiver position

Railway-induced ground vibrations – a review of vehicle effects

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

Human response to vibration in residential environments, technical report 1 : measurement of vibration exposure

The Technical Report 1 describes the research undertaken to develop a method by which human exposure to vibration in residential environments can be assessed. That work has been carried out by the University of Salford supported by the Department of environment food and rural affairs (Defra). The overall aim of the project is to derive exposure-response relationships for human vibration in residential environments. This document in particular focuses on the equipment and methodology employed to measure vibration from different sources. The main objective of this report is to describe the practical experience of implementing a vibration measurement protocol. Reported here are findings obtained in the field measurements and a description of a feasible method for measuring vibration for different sources. In addition, controlled tests performed to determine the suitability of the vibration mounting for various practical situations are reported

Study of the mitigation of tram-induced vibrations on different track typologies

Nowadays there is a growing development of urban tram and underground networks with the aim of improving resident’s mobility and reducing the environmental impact. Among the issues related to this fact one finds the vibration generated by the vehicles and transmitted through the track and the ground. This may cause an important impact for both residents and structures. In order to study this phenomenon, a comprehensive campaign of measurements has been carried out in certain sections of the tram network in Alicante (Spain). In addition, an analytical model has been developed and calibrated with part of the data obtained. Using both experimental measures and the computer model vibration within the track is analyzed. Special attention is paid to the alleviation capability of the different materials and typologies present in the track. From this study, a strong relation between the Young Modulus and the frequency range alleviated by each material is obtained, and more rigid typologies are shown to be more efficient for low frequency vibrations which are the ones potentially disturbing for humans

Track Gauge Degradation Modelling on Small Urban Rail Networks: Zagreb Tram System Case Study

Track gauge is the most significant tram track geometry parameter. Its degradation, which manifests as gradual increase of gauge deviation from prescribed values during track exploitation, causes poor ride quality, reduces safety and triggers most of the maintenance activities. To optimize tram track maintenance procedures, it is necessary to increase the proportion of preventive maintenance at the expense of corrective maintenance. This requires creation of physical model of track degradation. Conducted survey of conventional track degradation models showed that, in order to quantify the influence of track design, construction and exploitation characteristics on gauge degradation, it is most favourable to adopt the mechanistic‐empirical modelling approach. Zagreb high‐capacity tram network presents an optimal testing ground for exploration of the possibilities for tram track gauge degradation model development. Analysis of modelling results gave new, practical insights about the effects of tram track design and construction elements and exploitation characteristics on gauge degradation. These models represent the first step towards predictive maintenance system establishment on Zagreb tram tracks

A tram-train system to connect the urban area of Cosenza to its province: A simulation model of transport demand modal split and a territorial analysis to identify adapted transit oriented development prospects

International audienceThe purpose of this paper is to study possible prospects of regional development and of public transport demand evolution, resulting in the implementation of a new tramtrain service to suburban and a tramway for urban area of Cosenza and Rende and for municipalities of Savuto valley, in the southern Italian region of Calabria. This is an area that in recent decades has seen significant phenomena of urban de‐population, with consequent problems of urban sprawl into neighbouring small cities and land consumption. The mobility system is heavily focused on the use of private cars as the main and often the only way to travel; causing obvious problems of traffic congestionand poor urban quality of life for citizens. The modern tramway system project, next to be realized, will connect the urban area of Cosenza and Rende with the University of Calabria. It is a first important structural intervention that will hopefully help to significantly increase public transport modal share and to promote implementation of Transit Oriented Development policies, properly adapted to that specific territory. The decision to adopt such a narrow gauge tramway line, allows to consider the prospect of actually integrating this service with a tramtrain system linking Rogliano and municipalities of Savuto valley, with the urban area, using existing narrow gauge railways of Ferrovie della Calabria (main regional train operators). With this purpose was developed a transport demand simulation model, using the Tranus system, to estimate the evolution of the transport demand modal split in that area, caused by such changes in the mobility system. Through a spatial analysis were showed bsome areas that might be interested by interventions of urban renewal and regeneration, with greater access to public transport services and Transit Oriented Development policies. Results of this analysis and the simulation model will be presented and discussed in detail in this paper

Monocular tracking of the human arm in 3D: real-time implementation and experiments

We have developed a system capable of tracking a human arm in 3D and in real time. The system is based on a previously developed algorithm for 3D tracking which requires only a monocular view and no special markers on the body. In this paper we describe our real-time system and the insights gained from real-time experimentation

CONTRIBUTION TO THE MODELIZATION, ANALYTICAL AND NUMERICAL, OF GENERATION AND PROPAGATION OF VIBRATIONS ORIGINATED BY RAILWAY TRAFFIC. ANALYSIS OF MITIGATION PROPOSALS

Tesis por compendioReal Herráiz, JI. (2015). CONTRIBUTION TO THE MODELIZATION, ANALYTICAL AND NUMERICAL, OF GENERATION AND PROPAGATION OF VIBRATIONS ORIGINATED BY RAILWAY TRAFFIC. ANALYSIS OF MITIGATION PROPOSALS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52247TESISCompendi