Influence of thermal loading on mechanical properties of. Kropp chalmers university of technology, division of applied acoustics, se41296 gothenburg. A fast timedomain model for wheelrail interaction demonstrated for the case of impact forces caused by wheel ats a. Wheel rail profile management poor wheel rail contact, particularly in curves, reduces the effective steering capacity of the cars negotiating these curves. Both wheels and rails are prone to develop quasisinusoidal irregularities, which are. Rail wheel interface systems focus on understanding the dynamic interaction between the rail wheel and the rail while the vehicle is in motion. Introduction the selection of the cross sectional profile for the wheel of railway vehicles is a typical engineering compromise and has challenged railway engineers since the time of. Therefore, there is a competing and restrictive relationship between fatigue cracks and wear. Damage typically manifests itself as wear or crack. Part one provides the fundamentals of contact mechanics, wear, fatigue and lubrication as well as stateoftheart research and emerging technologies related to the wheel rail interface and its management.
Damage analysis of wheelrail contact associated to high. Reducing wheel climb at switch points to reduce derailments. It is the result of a compromise when a locomotives wheels are unbalanced to offset horizontal reciprocating masses, such as connecting rods and pistons, to improve the ride. By bob tuzik for three years running, new york city transit and the federal transit administration have kicked off the annual wheelrail interaction rail transit conference with discussion of the nyctfta research project to explore integrated wheelrail analytics on mtanycts no. Better understanding of wheel rail interfaces is therefore critical to improving the capacity, reliability and safety of the railway system. Wheel rail profiles and vehicle steering behavior are such that the curve can be considered mild the contact area at each wheel tread low rail interface is approximately circular. Third body separates wheel and rail surface, accommodates velocity differences and determines wheelrail friction. The effect of profiles on wheel and rail damage, int.
Analysis of rolling contact fatigue damage initiation at the wheelrail interface. A train wheel or rail wheel is a type of wheel specially designed for use on rail tracks. The outer circumferential surface of the rim, which con. In order to reduce the dynamic wheelrail impact between wheels and turnout rails, flange bearing frogs can be applied to prolong turnout service life while. Ensure that the facility is free from spillage and wheel contamination. Thermal damage and rail load stresses in a 33inch railroad car wheel h. As the wheelrail contact is an open system, the adhesion between the wheel and rail is inevitably affected by contaminants. This chapter describes the processes of damage by solid materials and film formation by liquids and shows how traction is affected by both. Sanding is used in train operation to improve adhesion at the wheelrail interface in both braking and traction.
The drive and braking performance of new locomotives and multiple units have. The current thesis focuses on modelling wheel rail contact under high adhesion condition, and explanation of the subsequent damage formation on the rail. The project, reducing wheel climb at switch points to reduce derailments, is part of the safety idea program, which is funded by the federal. Wheelrail damage and its relationship to track curvature. Analysis of railway wheel to study thermal and structural behaviour pramod murali mohan abstract wheelrail systems are intensively subjected to damage caused by rolling contact and slip behaviour between the wheel and. Abnormal wheel motion patterns can be caused because of poor rail profile or poor track geometry leading to damage to both wheels as well as the rails. Analysis of rolling contact fatigue damage initiation at. This paper outlines the historical development of the wheel and rail profiles currently used on railway vehicles. An approximate analysis for hertzian elliptical wheelrail. Wheel rail engineer for a demonstration of our efforts interest from several other agencies including cta, and mbta in how to better their systems bart wheel rail optimization. Article information, pdf download for use of railway wheel wear and. A study of railway wheel profile parameters used as indicators of an increased risk of wheel defects. This is the expected wheelrail contact position of a wheel in the lead wheelset position of a truck, while riding on the low inside rail of a curve. A study of railway wheel profile parameters used as indicators of an increased risk of.
Rcf irt rail grinding steenbergen rev1 v04 tu delft research. The wheelrail impact forces occur whenever a wheel flat on the wheel tread meets the rail. Wheel contamination from consumer products like flour, canola oil and cornstarch can reduce braking capacity and cause other problems with rail equipment. In the sca skog wagon fleet run by hector rail, wheel damages are a serious. Returning rail wheel sets can be carried out using overfloor or underfloor machines and dry machining conditions. Severe wear is a common damage mechanism in railway turnouts, which strongly. This article describes the wheelrail interface management wrim model being developed by. This paper presents the performance of a realtime railwheel wear damage control system with respect to different operation conditions. Wheel flange wear inspections can be done visually, or by manual. To form a database for sampling, 120 wheel profiles from. It also presents the key damage mechanisms involved in wheel rail contact and summarises the methods that have recently been developed by railway engineers to predict the level of wheel and rail damage from these mechanisms. Turnout, profile wear, wheelrail contact, dynamic interaction, finite element. These and other similar substances can cause serious incidents and equipment damage when cars are being moved.
The fatigue problem of railroad wheels, referred to as rolling contact fatigue 2, is caused by. Pdf the influence of wheelrail contact conditions on the. The current thesis focuses on modelling wheelrail contact under high adhesion condition, and explanation of the subsequent damage formation on the rail. Many of the wheels that were removed for wear causes were found to have noncondemnable shelling and spalling, indicating that tread damage is more prevalent than repair records would indicate.
This causes damage to the wheel and rail surface and can accelerate wear. Wheelrail profile management poor wheelrail contact, particularly in curves, reduces the effective steering capacity of the cars negotiating these curves. Table of contentsrepair damage axle beam bottom rail combination front, refrigeration unit opening corner post crossmember, intermediate crossmember, over landing gear crossmember, over suspension crossmember, pintle hook mounting diamond plate, floor, diamond plate overlay diamond plate, threshold plate door frame, side door. The model provides a better understanding of the influences of high adhesion condition on contact stress states, damage initiation and also temperature rise on the rail. Abrasive particles are applied to the wheelrail contact to restore traction when low adhesion situations exist on the rail head. Part one provides the fundamentals of contact mechanics, wear, fatigue and lubrication as well as stateoftheart research and emerging technologies related to.
The effects of curve radius and applied traction on the magnitude and direction of tangential force are illustrated below for a vehicle with fairly conventional suspension. The following factors are found to be detrimental to wheel fatigue life. During that time, my main areas of interest have been in rail corrugation for which railmeasurement provide measuring equipment, as shown elsewhere on this website, rolling contact fatigue rcf. The hammer blow may cause damage to the locomotive and track if the wheel rail force is high enough. If wheel rail contact occurs at the flange root of the wheel, or at a false flange on the tread that has developed due to wear, contact stresses can become extremely high. The greatest influences on tangential force are curve radius, applied traction, bogie design and applied cant. Analysis of railway wheel to study thermal and structural. Rail sections tee rail data diagram dimensions for tee rail data table ht height bw width of base hw width of head. Pdf simulation of wheelrail contact and damage in switches. Wheel load 78 kips maximum with lifted load wheel spacing 11. Reducing the spread between worn and unworn profiles, and in particular reducing the concavity of worn wheels, can significantly improve curving and ride quality of bogies, decrease wheel rail damage and increase wheel and rail lifespan. Railwheel systems cm2003 in gothenburg, sweden june 10, 2003 submitted to wear journal june 2003 optimal design of wheel profile for railway vehicles i. Wheelrail interface handbook is a onestop reference for railway engineering practitioners and academic researchers. Pdf the susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material.
Pdf a study of railway wheel profile parameters used as. This specification details the allowable limits for the inspection of all rail vehicle wheels for various tread and flange defects. Wheel rail systems are inherently subject to damage caused by the rolling contact and slip stick behaviour between the wheel and the rail. When wheel rail damage in terms of wear and rcf can be predicted, measures can be taken to decrease it. Wheel flats and severe rcf damage, apart from having a large impact on noise generation, might also cause safety problems. Pdf the effect of profiles on wheel and rail damage. Railways, railway track, railwheel interaction, wheelrail contact, rolling contact fatigue rcf. Inspections of tread damaged wheelsets rail transportation. Railroad wheel rim damage occurs due to both fatigue and wear failure mechanisms. When wheelrail damage in terms of wear and rcf can be predicted, measures can be taken to decrease it. Wheel rail conditions can be far from ideal in actual railway service.
The wear that shapes wheel and rail profiles has a profound effect on curving performance and dynamic stability of bogies. Grinding of wide gage track must remove a substantial amount of metal from the field side to protect the rail from wheel false flange damage. The hammer blow may cause damage to the locomotive and track if the wheelrail force is high enough. The wheel profile damage model wpdm 1 was used in this study, to predict wheel wear using the sliding model method. I have worked on railhead damage of various types for almost my entire working life. Investigation on wheelrail contact and damage behavior in a. In particular, an investigation into the wear growth rate. In regions away from the contact area, the theoretical predictions are verified by experiment. Thermal damage and rail load stresses in a 33inch railroad car wheel. It is an outofbalance force on the wheel known as overbalance. This appreciably increases the rolling resistance of trains on curved track, significantly impacting fuel consumption, track forces, and wheel and rail wear. Third body at wheelrail contact third body is made up of iron oxides, sands, wet paste, leaves etc. Development of an onboard measurement system for railway. Wheel damage wheel flats formed by a locked wheel sliding on a rail part of the wheel becomes flattened thermal damage and martensite may form at the flat causes high impact loads that may result in cracking, noise and discomfort.
Wheel damage and maintenance of sca skog wagons diva portal. The current paper presents the analysis of rcf damage initiation and stress distribution at the wheelrail interface at different directions. Wheelrail friction depends on the shear properties composition of the third body layer. This article explores the effects of profile wear on contact behaviors in the wheelrailswitch contact and dynamic interaction, and nominal and measured worn turnout rail profiles. For example, the combination of wheel and rail profiles, or the combination of vehicle and track, can be optimised to control the damage. Moreover, they induce large impact forces, see figure 1. Modelling of rough wheelrail contact for physical damage calculations. Wheel rail profiles and vehicle steering behavior are such that the curve can be considered mild the contact area at each wheel tread low rail interface is approximately circular, with a typical radius of 7mm. Shows a 12 inch 300mm radius gage on the low rail and the damage caused by the false flange.
It has been a wellestablished fact that excessive wheelrail loads cause accelerated wheelrail wear, truck component deterioration, track damage, and increased potential for derailment. A rolling component is typically pressed onto an axle and mounted directly on a rail car or locomotive or indirectly on a bogie uk, also called a truck north america. Wear damage of outofround wheels in rail wagons under. This appreciably increases the rolling resistance of trains on curved track, significantly impacting fuel. Simulation and measurement of wheel on rail fatigue and wear. Wheelrail wear and surface damage caused by adhesion sanding. Liquids, especially highviscosity oils, can form a partially separating film between the wheel and rail and so reduce traction. Use of railway wheel wear and damage prediction tools to improve. A proper understanding of the effects of heavier wheel loads on rail performance cannot be obtained without consideration of other factors such as wheelrail profile, im proved strength and cleanliness of rail steel, and wear, that is, grinding. Realtime railwheel wear damage control request pdf.
Pdf rolling contact fatigue rcf results in damages on the railhead. Interface journal the journal of wheelrail interaction. High contact stresses can lead to additional wheel defects, such as shelling, in service. Pdf analysis of rolling contact fatigue damage initiation at the. The text outlines the action to be taken when defects are found. Proceedings of the institution of mechanical engineers. The rail steel can be assumed to have a shear yield strength of k70 ksi. Methods of optimising the wheel and rail profiles to reduce the overall damage and therefore improve the efficiency of the railway system are discussed and a case study from the uk of an antircf. Periodic deviation of the diameter of wheel across its circumference is referred to as the outofround oor defect that can cause significant damages to wheel rail interface, affect the service life of various components of the vehicletrack system and the safety of trains. Allowable speeds mentioned below are not to exceed the prevailing track speed limit. To form a database for sampling, 120 wheel profiles from freight wagons in regular traffic have been measured and categorised with respect to wear. In recent years, increased train speeds and axle loads have increased the contact stresses, thereby changing the major wheel rim damage mechanism from wear to fatigue 1. The current paper presents the analysis of rcf damage initiation and. Continuous observation of wheel rail contact forces in.
Wheel steel requirements according to uic 8123 and en 262 3 wheel tread damage current situation the demands placed on materials used for wheels and rails have grown with the introduction of highperformance rail traffic. As part of this activity, national the study team examined inter standards and practices from several major international rail systems and compared them. Use of railway wheel wear and damage predictions tools to improve. They include a hub, wherein an axle is inserted, a rim that contacts the rail, and a web that unites the two parts. Returning adds life to train wheels unique turning considerations and circumstances come into play when returning wellworn freight and metro rail wheels. Wheels are cast or forged and are heattreated to have a specific hardness. Specify section and weight of rail and width of crossing. Contaminants, which refer to foreign substances applied both intentionally and unintentionally the wheel to rail interface, can make wheelrail adhesion either too high or too low and to difficult predict. Physical damage models require rough contact surfaces in order to obtain stresses high enough for fatigue damage occurring. Wheelrail systems are inherently subject to damage caused by the rolling contact and slip stick behaviour between the wheel and the rail. Use of railway wheel wear and damage predictions tools to.
Severe wear is a common damage mechanism in railway turnouts, which strongly affects the dynamic performance of railway vehicles and maintenance costs of tracks. Pdf analysis of rolling contact fatigue damage initiation. Jul 08, 2009 this is the expected wheel rail contact position of a wheel in the lead wheelset position of a truck, while riding on the low inside rail of a curve. The considered parameters are wheel profile and wheelrail friction coefficient. Reducing the spread between worn and unworn profiles, and in particular reducing the concavity of worn wheels, can significantly improve curving and ride quality of bogies, decrease wheelrail damage and increase wheel and rail lifespan. A solid wheel of a railway vehicle hereinafter wheel consists of three parts, as shown in fig. Jul 22, 2010 the following factors are found to be detrimental to wheel fatigue life. Thus, true shelling is not related to wheel sliding, braking systems or braking ratio, and is. Esveld section of road and railway engineering faculty of civil engineering and geosciences, delft university of technology stevinweg 1, nl2628, cn delft. Keywords wheelset maintenance, wheel wear and rail damage, wear. Thermal damage and rail load stresses in a 33inch railroad. Fatigue analysis of the effects of wheel load on rail life. Rolling contact fatigue rcf results in damages on the railhead surface and wheel tread. Materials used for wheels on rolling stock railway research.
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