Rail wear can result in extensive costs for the track owner if it is not predicted and preventedin an efficient way. To limit these costs, one measure is to predict rail wear through wear simulations. The purpose with this work is to perform simulations of successive rail wear on the Swedish light rail line Tvärbanan in Stockholm, by means of the track-vehicle dynamics software GENSYS in combination with a wear calculation program developed in MATLAB. The simulation procedure is based on a methodology with a simulation set design, where the simulations to be performed are selected through a parametric study. The simulations include track-vehicle simulations, where the wheel-rail contact is modelled according to the Hertzian contact theory together with Kalker’s simplified theory (including the numerical algorithm FASTSIM). The results from the track-vehicle simulations serve as input to the wear calculations. When modelling rail wear Archard’s wear model has been used, including wear coefficients based on laboratory measurements. The measurements have been performed under dry conditions, so the wear coefficients under lubricated conditions (both natural and deliberate lubrication) are reduced by factors estimated by field observations. After the wear depth calculations the wear distribution is smoothed and the rail profile is updated. The simulation procedure continues with a new wear step as long as the desired tonnage is not attained. Four curves of Tvärbanan with different curve radii, ranging from 85 to 410 m, have beenstudied in this work. On three of the curves the high rail is deliberately lubricated, whereas no lubrication has been applied in the widest curve. The vehicle operating the light rail line is an articulated tram with two motor end bogies and one intermediate trailer bogie. The line was opened in August 1999 and extended in one direction one year later. Rail profile measurements have been carried out by SL since March 2002. The traffic tonnage at the selected sites from the opening of the line to the last measurement occasion (September2004) is at most 8.9 mega gross ton per track. The results of the rail wear prediction tool are evaluated by comparing worn-off area of the simulated rail profiles with that of the measured rail profiles. Simulated and measured resultsdo not agree too well, since the simulated rail wear is more extensive than the measured one, especially on the outer rail. However, the shapes of the simulated worn rail profiles are comparable to those of the measured rail profiles. / QC 20101123

In recent years there has been continuous increase of axle loads, tonnage, train speed, and train length which has increased both the productivity in the rail sector and the risk of rail breaks and derailments. Rail operating risks have been increasing due to the increased number of axle passes, sharper curves, wear-out of rails and wheels, inadequate rail-wheel grinding and poor lubrication and maintenance. Rolling contact fatigue (RCF) and wear are significant problems for railway companies. In 2000, the Hatfield accident in the UK killed 4 people, injured 34 people and led to the cost of £ 733 million (AUD$ 1.73 billion) for repairs and compensation. In 1977, the Granville train disaster in Australia killed 83 people and injured 213 people. These accidents were related to rolling contact fatigue, wear and poor maintenance. Studies on rail wear and lubrication, rolling contact fatigue and inspection and rail grinding analyse and assess the asset condition to take corrective and preventive measures for maintaining reliability and safety of rail track. Such measures can reduce the operational risks and the costs by early detection and prevention of rail failures, rail breaks and derailments. Studies have so far been carried out in isolation and have failed to provide a practical solution to a complex problem such as rail-wheel wearfatigue-lubrication-grinding-inspection for cost effective maintenance decisions. Therefore, there is a need to develop integrated economic models to predict expected total cost and operational risks and to make informed decisions on rail track maintenance. The major challenges to rail infrastructure and rolling stock operators are to: 1. keep rolling contact fatigue and rail-wheel wear under controllable limits, 2. strike a balance between rail grinding and rail lubrication, and 3. take commercial decisions on grinding intervals, inspection intervals, lubrication placements, preventive maintenance and rail replacements. This research addresses the development and analysis of an integrated model for assessment of operational risks in rail track. Most significantly, it deals with problems associated with higher axle loads; wear; rolling contact fatigue; rail defects leading to early rail replacements; and rail breaks and derailments. The contribution of this research includes the development of: failure models with non-homogenous Poisson process and estimation of parameters. economic models and analysis of costs due to grinding, risks, downtime, inspection and replacement of rails for 23, 12, 18 and 9 Million Gross Tonnes (MGT) of traffic through curve radius 0-300, 300-450, 450-600 and 600-800 m; and application of results from this investigation to maintenance and replacement decisions of rails. Cost savings per meter per year are: * 4.58% with 12 MGT intervals compared to 23 MGT intervals for 0-300 m * 9.63% with 12 MGT intervals compared to 23 MGT intervals for 300-450 m * 15.80% with 12 MGT intervals compared to 23 MGT intervals for 450-600 m * 12.29% with 12 MGT intervals compared to 23 MGT intervals for 600-800 m. a lubrication model for optimal lubrication strategies. It includes modelling and economic analysis of rail wear, rail-wheel lubrication for various types of lubricators. Cost effectiveness of the lubricator is modelled, considering the number of curves and the total length of curves it lubricates. Cost saving per lubricator per year for the same curve length and under the same curve radius is: * 17% for solar wayside lubricators compared to standard wayside lubricators. simulation model for analysis of lubrication effectiveness. Cost savings per meter per year for: * 12 MGT grinding interval is 3 times for 0-450 m and 2 times for 450-600 m curve radius with lubrication compared to without lubrication. * 23 MGT grinding interval is 7 times for 0-450 m and 4 times for 450-600 m curve radius with lubrication compared to without lubrication. a relative performance model, total curve and segment model. an inspection model for cost effective rail inspection intervals. Cost savings per year for same track length, curves and MGT of traffic: * 27% of total maintenance costs with two inspections, compared to one inspection considering risk due to rail breaks and derailments. a risk priority number by combining probability of occurrence, probability of detection and consequences due to rail defects, rail breaks and derailments. integrated model combining decisions on grinding interval, lubrication strategies, inspection intervals, rectification strategies and replacement of rails. Cost saving per meter per year for 12 MGT is: * 5.41% of total maintenance costs with two inspections, compared to one inspection considering risk due to rail breaks and derailments. * 45.06% of total maintenance costs with lubrication for two inspections, compared to without lubrication. Cost saving per meter per year for 23 MGT is: * 5.61% of total maintenance costs with two inspections, compared to one inspection considering risk due to rail breaks and derailments. * 68.68% of total maintenance costs with lubrication for two inspections, per year compared to no lubrication. The thesis concludes with a brief summary of the contributions that it makes to this field and the scope for future research in wear-fatigue-lubrication-grinding-inspection for maintenance of rail infrastructure.

Wear transitions in the wheel–rail contact are of increasing interest since the general trend in railway traffic is toward increased velocities and axle loads. Curving increases the risk of flanging, causing the contact to change from an almost pure rolling wheel tread–rail head contact to more of a sliding wheel flange–rail gauge contact on the high rail in curves. Under wheel flange–rail gauge contact conditions, wear transitions to severe or catastrophic wear will occur if the contact is improperly lubricated. Such a transition is the most undesirable transition in the wheel–rail contact, as it represents a very expensive operating condition for railway companies. The contact conditions responsible for this transition are very severe as regards sliding velocity and contact pressure, and thus place high demands on both the lubricant and the wheel and rail materials. The focus of this thesis is on the transitions between different wear regimes in a wheel–rail contact. Wear is discussed both in traditional tribological terms and in terms of the categories used in the railway business, namely mild, severe and catastrophic wear. Most of the work was experimental and was performed at the Royal Institute of Technology (KTH), Department of Machine Design. The effects of contact pressure, sliding velocity, and type of lubricant have been investigated, producing results that resemble those of other studies presented in the literature. The absence of research relating to the wheel flange–rail gauge contact is addressed, and it is concluded that a lubricant film must be present on rails in curves to prevent severe or catastrophic wear. The formulation of this lubricant can further increase its wear- and seizure-preventing properties. To obtain a deeper understanding of wear transitions, methods such as airborne particle measurement and electron microscopy have been used. Paper A presents the test methodology used to detect seizure and discusses the wear-reducing influence of free carbon in highly loaded contacts. Paper B presents the testing of seizure-initiating conditions for a range of environmentally adapted lubricants applied to wheel and rail materials; a transient pin-on-disc test methodology was used for the testing. Paper C presents the use of pin-on-disc methodology to study the wear-reducing effects of a wide range of lubricants. The best performing lubricant was a mineral oil containing EP and AW additives. Paper D relates wear rates and transitions to airborne particles generated by an experimentally simulated wheel–rail contact. The airborne particles generated varied in size distribution and amount with wear rate and mechanism. Paper E relates additional analysis techniques, such as FIB sectioning, ESCA analysis, airborne particle measurements, and SEM imaging of airborne wear particles, to the contact temperature. / QC 20100721 / Samba 6

Orientador: Cassio Eduardo Lima de Paiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-06T06:46:08Z (GMT). No. of bitstreams: 1 Semprebone_PauladaSilva_M.pdf: 2252000 bytes, checksum: 59351d3c7428a44235337a6191251e14 (MD5) Previous issue date: 2005 / Resumo: O assunto a ser abordado nesta pesquisa refere-se ao componente da superestrutura ferroviária trilho, especificamente aos defeitos que nele se verificam em conseqüência de sua utilização como guia para o material rodante e transmissor de esforços decorrentes do movimento do veículo, e do desgaste do contato roda-trilho. A importância de se realizar este estudo fundamenta-se na necessidade de se conhecer detalhadamente os defeitos e o limite de desgaste do trilho, que permitem determinar sua vida útil, para que se possa evitar ao máximo sua substituição, devido ao alto custo envolvido, além da questão da segurança da via que, dependendo do defeito, pode ser comprometida. Para a realização do trabalho foi realizada uma pesquisa bibliográfica, objetivando reunir informações sobre o assunto e levantar dissertações existentes que buscam solucionar tais problemas. Busca-se, ainda, encontrar uma justificativa para o valor limite de desgaste adotado atualmente no meio ferroviário, que corresponde a 25% de perda em área do boleto do trilho, através de simulações do desgaste utilizando-se um modelo computacional, além de rotinas de cálculo que permitam verificar se esse parâme1rO é restrição do . ponto de vista do dimensionamento do trilho. Pretende-se, assim, a1ravés desta pesquisa proporcionar uma contribuição ao meio ferroviário, avaliando-se se o limite de desgaste adotado mos1ra-se adequado à realidade ferroviária / Abstract: The matters concerned in this research particularly refer to damages caused by stress while using tracks on permanent railways as guide and strain transmitter of the vehicles. Importance is attached to this study based on the need of understanding deep and in detail the faults and wear limits on the tracks, which allow determining its period of use, so that substitution may be avoided due to its high costs. Furthermore, the railway safety may be weaknessed depending on the sort of wear. This study has basis on a bibliographical research aiming to gather information and possible works on this field in order to solve the problems mentioned above, as well as finding proofs for the current wear rate accepted in the railway field, which is 25% of track area decrease, throughout wear simulations on a computer based model, besides calculations which allow stating whether this standard depends on the track size. This work claims to contribute to the railway field evaluating if the adopted wear rate meets our railway reality / Mestrado / Transportes / Mestre em Engenharia Civil

The diploma thesis deals with a rail wear in curves with a small radius (R < 500 m), in the national corridor railway, between stations Blansko and Svitavy. The diploma thesis deals with the impact of the track gradient, the horizontal layout of the track, traffic composition, and direction of travel on the size of the horizontal and vertical rail wear. Also, the influence of rail steel grade is discussed in the diploma thesis.

The thesis deals with the wear of rails in small radius curves and the possible influence of RailJet sets on the increase of wear in the section Brno-Maloměřice – Blansko. As part of the thesis, a search was made of the methods used to evaluate the use of rails. These methods are Vogel's method, Heumann's method and rail wear theory. Subsequently, these methods were applied to the selected sections and an overall evaluation was performed.

Ce travail réalisé dans le cadre d'une collaboration industrielle avec la société ALSTOM Transport porte sur l'étude de la dégradation des voies ferrées urbaines. Les composantes de voie retenus pour cette étude sont le rail et la dalle de voie en béton. Concernant le rail, différents problèmes sont abordés : contact roue – rail, usure du rail, usure ondulatoire du rail, et fatigue de contact de roulement (RCF) du rail. Un outil numérique avec des interfaces graphiques, nommé CONUS, est développé pour le problème de contact roue – rail et le problème d'usure du rail. Des théories classiques (Hertz, Kalker, Archard, etc.) sont implantées dans cet outil. La méthode stationnaire est implantée dans un code de calcul par éléments finis pour étudier l'état asymptotique de l'acier du rail sous le chargement répété des trains. Ceci nous permet de prédire les régimes de RCF du rail. La mécanique de l'endommagement est utilisée pour prédire la fatigue du matériau béton. Le formalisme de Marigo couplé avec le modèle d'endommagement de Mazars permet de modéliser la dégradation progressive de la rigidité du matériau sous chargement cyclique. Une campagne d'essais de fatigue du béton en flexion a été réalisée. Elle a pour but de valider le modèle théorique et d'identifier les paramètres du matériau. Le dimensionnement d'une dalle de voie en béton a fait l'objet d'une application de cette méthode. Le modèle de réseau de poutres (lattice model) a été utilisé pour étudier la propagation des fissures dans les structures en béton. Ce modèle a été implanté dans le logiciel de calcul par éléments finis, CESAR-LCPC. Les résultats numériques (propagation de fissures) obtenus pour les structures simples sous chargement statique sont en tout point comparables avec les résultats d'essais expérimentaux. Ce modèle a ensuite été utilisé pour étudier la fissuration sous chargement de fatigue. Pour cela un modèle d'endommagement simple modélisant la dégradation des éléments «poutres» s'est avéré suffisant pour décrire la cinématique de propagation des fissures / This work is part of the collaboration between the laboratory Navier (UMR ENPC /IFSTTAR/ CNRS) and ALSTOM Transport company (TGS/Trackway). It focuses on the study of the degradation of urban railways. The components of track considered in this study are the rail and the concrete slab. Regarding the rail, different problems are discussed : wheel – rail contact, rail wear, rail corrugation and rolling contact fatigue (RCF). A numerical tool with graphical interfaces, called CONUS, is developed to predict the behaviour of the wheel - rail contact, the rail wear, and the rail corrugation problems. Classical theories (Hertz, Kalker, Archard, etc...) are implemented in this tool. The stationary method is implemented in a finite element software to study the asymptotic state of the rail steel under repeated loading of trains.The damage mechanics is used to predict the fatigue life of concrete. Marigo's formalism coupled with Mazars' damage model is used to predict the gradual degradation of material stiffness under cyclic loading. A campaign of fatigue tests for concrete in bending was conducted. It aims at validating the theoretical model and identifying material parameters. We applied this method in order to design the concrete slabs of urban railway. The lattice model was used to study the crack propagation in concrete structures. This model was implemented in the finite element software, CESAR-LCPC. The numerical results obtained for simple structures under static loading are consistent with the results of laboratory experiments. This model was then used to study the crack propagation under fatigue loading. For that purpose, a simple damage model of degradation of the "beams" elements describes the kinematics of crack propagation with a satisfying accuracy