Gauge Widening Research Articles

Investigation of dynamic gauge widening in small radius curves and its impact on lateral wheel-rail contact forces

In this paper, the lateral interaction between a rail vehicle and the track is investigated during cases of an occurrence of dynamic gauge widening. This is composed of the nominal track gauge, wear of the rail profiles and track widening due to wheel-rail forces on sections of curved track. A multibody simulation model is used to investigate the various influencing parameters. This model not only analyses the single rail’s lateral displacement but also tilting. Furthermore, the simulation of rail pads with adjustable stiffnesses is enabled. The resulting different contact points between the wheel and rail are represented, affecting the wheel-rail contact forces. The results reveal that changes in contact geometry caused by rail tilting depend strongly on the specific wheel and rail profiles. This is illustrated by comparing a new rail profile with a heavily worn rail profile. Particular attention is also paid to the distinction between leading and trailing wheelsets. Finally, the model is validated using measured wheel-rail forces and rail head movement, as measured on the track. A better understanding of dynamic track widening can improve the running behaviour of the wheelset on small radius curves, help protect against derailment and reduce wear on the wheel and rail.

Causes and failure forms of railway wheels

Railway wheels are a crucial part of the system, which provide necessary traction on railway tracks by carrying cyclic loads. Therefore, it is important to understand the various failure mechanisms of railway wheel sets and the causes to prevent the failure for safety issues. All various railway wheel failures such as crack and rim, crack at rim and disc interface, circumferential chipping-off, wheel tread shelling, thermal crack on wheel tread, wheel tread wear, fatigue, creep, wheel gauge widening, and wheel gauge condemning and their corresponding causes also discussed in this manuscript. Further, it gives detailed wheel failure scenarios in tread and disc braking of locomotive, wagon, and coach wheels. The in-depth details of various wheel failure sceneries observed and analyzed from the field, and case studies are also reviewed in detail.

Predictive maintenance in railway systems: MBS-based wheel and rail life prediction exemplified for the Swedish Iron-Ore line

A successful predictive maintenance strategy for wheels and rails depends on an accurate and robust modelling of damage evolution, mainly uniform wear and Rolling Contact Fatigue (RCF). In this work a life prediction framework for wheels and rails is presented. The prediction model accounts for wear, RCF, and their interaction based on the output from MBS simulations to calculate the remaining life of the asset, given in mileage for wheels and MGTs for rails. Once the model is calibrated, the proposed methodology can predict the sensitivity of the maintenance intervals against changes in operational conditions, such as changes in contact lubrication, track gauge, operating speeds, etc. The prediction framework is then used in two operational cases on the Swedish Iron-Ore line. The studied cases are, the analysis of wheel life for the locomotives, and the analysis of rail life for gauge widening scenarios. The results demonstrate the capabilities of the MBS-based damage modelling for predictive maintenance purposes and showcase how these techniques can set the path towards Digital Twins of railway assets.

Updating the criteria for assessing the state of the railway track according to the data of track measuring equipment

Introduction. One of the consequences of the introduction of the Instructions for Assessing the Condition of the Rail Track (enacted on February 28, 2020 No. 436/r) was an increase in the number of newly detected deviations from the norm of track maintenance and their reassignment as malfunctions. As a result, the number of kilometres with limited train speeds has increased by up to 3 times, which may lead to significant losses in transportation and an increase in the cost of the immediate track maintenance.Materials and methods. Data from a special thoroughfare of a diagnostic complex along the operating lines of Russian Railways were used to analyse the actual distribution of types and magnitudes of malfunctions, the number and causes of the speed limits. The authors used computer simulations to determine the dynamic indicators of cars in accordance with the algorithm of the deterministic method for calculating the movement of cars along the railway track.Results. The consequences for assessing the state of the track from the standards specified in Instruction 436/r are analysed. The authors present the results of mathematical modelling of the rolling stock interaction with the track, confirming the feasibility of the proposed changes in the standards: increasing the permissible speeds of passenger trains, assessing the gauge widening in curved sections, clarifying the estimates of unbalanced acceleration.Discussion and conclusion. It is proposed to change a number of standards for assessing deviations from the norms of track maintenance in order to reduce the number of speed limits.

INFLUENCE OF TRACK GEOMETRY CONDITION MONITORING ON RAILWAY INFRASTRUCTURE MAINTENANCE PROCESSING

This study analyzed the usage of data of track geometry measurement for railway infrastructure maintenance processing support and estimated its influence on railway infrastructure maintenance decision-making. Especially, the approach assessment of the influence of track geometry monitoring on railway infrastructure processing. The well-timed maintenance of the arrangement of railway tracks in allowable conditions is sufficient for the smooth and steady running of rail vehicles. The mechanism of track gauge widening during exploitation is usually gradual and relatively long-lasting. When are not detected in a timely manner, the final track failures often arise under the effect of additional factors, such as surpassed train speed limit, poorly maintained and functioning running gear of a rail vehicle, misalignment of rails, and extreme dynamical effects. A questionnaire considering the influence of the application of track geometry monitoring was formulated. An expert review was completed in order to perform a comparative analysis of the features of track geometry monitoring with the greatest influence on railway infrastructure maintenance processing. The data collected from respondents were processed using a multi-criterion estimation method, especially an interactive fuzzy linear assignment method. Finally, basic conclusions and considerations are given.

Gauge widening failures of wagon wheels in Indian Railways: Finite element modeling and observed statistics

There were many gauge widening cases identified in wagon wheels of Indian Railways during the past decade, but no investigation was conducted to analyse the failures. The present work aims to investigate the main cause of failures in wagon wheels due to gauge widening. A train running model is used to estimate heat generation at wheel and brake block interface. A finite element model is used to estimate temperature and stress state in the wheel during heat treatment, wheel and axle fitment, and braking. Heat partition between brake blocks and wheel is considered for the analysis. Further, heat losses to the environment because of convection and radiation are also incorporated in the model. The wheel gauge reduces during the braking process and the permanent wheel gauge increases during the cooling process. Permanent wheel gauge increases with non-uniformity in braking and a higher frequency of braking.

Detection Method of Possible Derailment due to Gauge Widening Using On-vehicle Track Measurement Data

Detection Method of Possible Derailment due to Gauge Widening Using On-vehicle Track Measurement Data

Effect of periodic wheel tread reprofiling on wheel gauge evolution in the wheelsets of tread-braked coaches: Finite element modeling and field observations

Field statistics of the wheelsets of gauge-widened coaches in the Indian Railways show higher tendency for excessive wheel gauge widening for lower diameter wheelsets. Additionally, the axial flange deflection in gauge-widened wheelsets increases nearly linearly with the radial distance. In this work, a finite element model is developed to investigate the reasons behind these field observations. The model considers heat generation during braking, heat loss to rail, brake blocks, ambient air, residual stresses generated during wheel manufacturing, and material removal during wheel reprofiling. Wheel gauge evolution is studied for different braking histories, including those that span the entire life period of the wheel, i.e. as the wheel diameter reduces from its initial to minimum allowable size. Simulations show that higher wheel rim temperatures and lower wheel stiffness, for lower diameter wheels, result in higher wheel gauge widening for these wheelsets. Wheel gauge widening occurs primarily due to bending at the hub–disc interface; consequently, the axial flange deflection increases linearly with the radial distance.

Track loading on Russian Railways under modern maintenance conditions

Rail fasteners loading and its influence on the track deformability under modern maintenance conditions with increased cars axle loads is observed. The difference between oneand two-point wheelrail contact loading scheme is shown. The authors present the analysis of domestic and foreign methods of pads bench tests and show the necessity of carrying out tests imitating real (two-point contact) loading of pads. The bench test method for researching fastener loading and pad strain characteristics in a wide range of vertical and lateral loads under two-point contact scheme based on a number of field tests is presented. The results of static tests and following dynamic ones with cycling loading, which were carried out on a two-sleepers bench, are observed. Bench tests carried out by VNIIZHT and the analysis of the cyclic test methods showed the importance of fasteners tests with a real loading simulation making it possible to explain the causes of track gauge widening and decrease of track inclination, which considerably influences track stability and wear of the track and rolling stock.

Rejection Rate Analysis on Rail Wheels

These analysis ambitions to ascertain the major core cause of failures of rail wheels and to prevent the occurrence of same in future. One working model of train is developed to estimate the heat generated at brake pad-wheel and rail-wheel interfaces for locomotive and wagon wheels using the performance characteristics of brake blocks, the slip characteristics of wheel-rail traction and the resistance characteristics of a running train for given operating and braking conditions. The heat dissipation characteristics of rail-wheel and brake pad units interfaces in locomotive and wagon wheels and wheel running temperatures for different wheel profiles for different train running conditions are estimated. This work is carried out to identify the under-lying machinery of locomotive wheel failure due to widening and condemning of gauge. It has also accomplished the investigation on the impact of the type of brake block, wheel profile and braking conditions on locomotive wheel fiasco from gauge widening and condemning are also been carried out. It is suggested to use a high friction coefficient composite brake block results in higher wheel temperatures and cause large gauge changes, particularly for independent braking. Further, S-shaped wheels are found to be best suitable for avoiding undue gauge reduction or increase.

Laboratory analysis of track gauge restraining capacity of center-cracked railway concrete sleepers with various support conditions

Abstract As the number of concrete railway sleepers has steadily grown in North America, the importance of understanding the performance and failure of these components has also increased. Concrete sleepers typically perform better than timber sleepers to maintain track geometry and have a longer expected service life. Nevertheless, there have been derailments that were caused by excessive increase of track gauge due to deteriorated concrete sleepers and fastening systems. As ballast support conditions are closely related to sleeper performance, there is a need to fully understand the behavior of poorly supported sleepers. To quantify the influence of support conditions on sleeper deflection and gauge widening, laboratory experiments were performed. Using a static structural loading frame, new and center-cracked concrete sleepers were subjected to different support conditions, engineered using rubber pads. Simulated conditions included center bound sleepers, newly tamped track, and track under high impact loads. This paper presents a correlation between ballast support conditions and their effect on concrete sleeper health and track gauge. Using statistical tools to analyze the experimental results, it is shown that there is no significant difference between new sleepers and lightly center-cracked sleepers. Even extreme deterioration at the sleeper center has little influence on the gauge widening effect due to sleeper bending. Moreover, the gauge widening effect due to pure concrete sleeper bending seemed to be minimal, but not insignificant when compared to the amount of track gauge increase due to other track infrastructure conditions. Therefore, railway accidents where damaged concrete sleepers fail to restrain track gauge are more likely to be related to the rail seat, fastening system, or other production problems rather than center cracking.

Analysis of coupler jackknifing and its effect on locomotives on a tangent track

Coupler jackknifing has caused a number of derailments, and it is a significant topic that needs in-depth studies. This paper aims to investigate the characteristics of coupler jackknifing and its effects on the dynamic performance of locomotives during braking. A field braking experiment using three eight-axle locomotives was conducted on a tangent track. The experimental results indicated that in-service couplers with a friction arc surface are prone to coupler jackknifing once the compressive force of the coupler exceeds 400 kN. After coupler jackknifing, the coupler angle has a significant positive correlation with the yaw angle of the car body; both coupler jackknifing and coupler angle increase rapidly to maximum values. The contact between the car body and the bogie seriously affects the dynamic performance of the locomotive and causes lateral instability of the locomotive. In particular, the lateral deviation of the coupling couplers generates an eccentric wear on the tail of the coupler. A numerical simulation model is developed to investigate the effect of coupler jackknifing on the running safety of the locomotive. Simulation results show that coupler jackknifing induces an excessive lateral force on the wheelset and increases the risk of derailments and gauge widening. Compared with the existing measures against coupler jackknifing, in this study, an effectively active measure is proposed to improve the stability of the coupler and to prevent possible derailments caused by coupler jackknifing during braking.

Switch Panel wear loading – a parametric study regarding governing train operational factors

ABSTRACTThe acting forces and resulting material degradation at the running surfaces of wheels and rail are determined by vehicle, track, interface and operational characteristics. To effectively manage the experienced wear, plastic deformation and crack development at wheels and rail, the interaction between vehicle and track demands a system approach both in maintenance and in design. This requires insight into the impact of train operational parameters on rail- and wheel degradation, in particular at switches and crossings due to the complex dynamic behaviour of a railway vehicle at a turnout. A parametric study was carried out by means of vehicle-track simulations within the VAMPIRE® multibody simulation software, performing a sensitivity analysis regarding operational factors and their impact on expected switch panel wear loading. Additionally, theoretical concepts were cross-checked with operational practices by means of a case study in response to a dramatic change in lateral rail wear development at specific switches in Dutch track. Data from train operation, track maintenance and track inspection were analysed, providing further insight into the operational dependencies. From the simulations performed in this study, it was found that switch rail lateral wear loading at the diverging route of a 1:9 type turnout is significantly influenced by the level of wheel–rail friction and to a lesser extent by the direction of travel (facing or trailing). The influence of other investigated parameters, being vehicle speed, traction, gauge widening and track layout is found to be small. Findings from the case study further confirm the simulation outcome. This research clearly demonstrates the contribution flange lubrication can have in preventing abnormal lateral wear at locations where the wheel–rail interface is heavily loaded.

A Nordic heavy haul experience and best practices

This article summarizes the experiences gained at the Nordic heavy haul line “Malmbanan” located in Northern Sweden and Norway during the years 2007 to 2015 and the resulting best practice. Unique long-term information of field trials and monitoring from the on-going development for maintenance of rail and wheel has been described. The reported results come from the rail profile measurements using MiniProf and HC-recordings with Eddy-current devices and visual inspection on 43 test sections. The monitoring has been continuous since the project started, to reveal a deep insight into the complex wheel–rail interaction and provide understanding of the effect of applying optimized specifications. This was particularly important in view of the increasing traffic load that contributed to doubling of the yearly grinding campaigns. This article presents in particular the new MB5 profile, the wear rate behaviour between two different curves, impacts of gauge widening on rail rolling contact fatigue and the speed of gauge widening as well as the seasonal impact on the crack propagation. The presently applied maintenance strategy is discussed together with other experiences. The article finishes with some conclusions and an outlook into further work.

Gauge widening of passenger coach wheel sets in Indian Railways: Observed statistics and failure analysis

Abstract Several hundreds of gauge widening cases have been reported in coaching stock wheel sets of Indian Railways over the last two years. This work investigates the effect of non-uniformity in braking, brake load, braking frequency, wheel profile, and braking cycles on wheel gauge evolution in coach wheel sets with an aim to identify root cause of the problem. A validated finite element model considering heat generation at brake-wheel interface, heat partitioning at wheel-brake block and wheel-rail interfaces, and convective, radiative heat loss to ambient air is used to estimate wheel temperatures, stresses, and gauge change. Residual stresses generated during wheel manufacturing and fitment of wheel onto axle are considered in the study. It is found that wheel gauge reduces during braking and increases as wheels subsequently cool down. Magnitude of temporary gauge reduction and permanent gauge widening increases with increasing heat input. Thus, higher non-uniformity in braking – leading to overheating of some wheels – can cause wheel gauge widening. Interestingly, reduction in brake load reduces permanent gauge widening but increases temporary gauge reduction during braking. Nature of gauge change and effect of wheel profile, seen from gauge widening statistics, correlate well with findings from simulations.

Locomotive wheel failure from gauge widening/condemning: Effect of wheel profile, brake block type, and braking conditions

A finite element model accounting for heat partitioning at brake block–wheel and rail–wheel interfaces is used to investigate the effect of locomotive wheel profile, wheel diameter, brake block type, nature of braking (independent, synchronized, and drag), braking frequency and braking cycles on wheel gauge for tread braked, locomotive wheel sets. A train running model estimates heat generation rates during braking for assumed operating and braking conditions. Wheel profiles and brake block types used in the work, match with that used by Indian Railways. Bending at hub–disc and disc–rim interfaces is seen to primarily control axial deflection of wheels. While gauge reduction is observed during braking, gauge increase is seen during subsequent cooling. Maximum gauge increase occurs as the wheels finally cool down to room temperature. S-shaped wheels are seen to be better suited than straight plate and parabolic profile wheels for avoiding excessive gauge change. Locomotive wheel failure from gauge widening and condemning, albeit at different times, is seen to occur with independent braking for locomotives fitted with straight plate, S-shaped as well as parabolic profile wheels.

Locomotive wheel failure from gauge widening/condemning: Finite element modeling and identification of underlying mechanism

Gauge change in straight plate, locomotive, railway wheels is studied using finite element analysis. The study accounts for residual stresses generated during wheel manufacturing and fitment of the wheel on locomotive axle. A validated thermal model accounting for heat loss to rail, brake blocks and ambient air is considered for accurate prediction of wheel temperatures for a given train running and braking history. Results are obtained for low- and high-friction, composite brake blocks used by Indian Railways for two limiting braking scenarios: (i) synchronized braking where braking effort is uniformly distributed on all brake blocks and (ii) independent braking where braking effort to decelerate a train is provided solely by locomotive brake blocks. Results show that bending at hub–disc interface predominantly governs the gauge change. While compressive hoop stresses in the tread region, occurring from rim heating during braking, cause gauge reduction, tensile hoop stresses in the tread region, occurring during wheel cool down cause an increase in wheel gauge. Importantly, while gauge condemning is a transient phenomenon occurring only during braking, gauge widening is “permanent” as it exists even after the wheels cool to room temperature. Allowable reduction of wheel gauge of 0.5mm, currently used by Indian Railways, is found to be highly restrictive. In fact, in service wheel failure based on this criterion is observed in all braking scenarios considered.

Analysis of Track Gauge Widening in Curves with Small Radius

In this paper it was performed curve negotiation analysis of three axle bogie of locomotive type JŽ 461. This locomotive has large distance between first and middle i.e. middle and last axle, which leads to increased lateral forces during curve negotiation. Final result might be widening of track gauge in curves with small radius. This paper points that Infrastructure Manager must take into account vehicle performances and type of track when defines track gauge in curves.

Influence Evaluation of Fastener Stiffness Match on Subway Rail Switch Safety

To study the influence law of fastener stiffness match on subway rail switch safety, and select appropriate stiffness, the No.9 subway switch was taken as an example in this paper to carry out all the following work. Based on finite element method, the influence of fastener stiffness match on the vertical dynamic relative displacement of switch rail and dynamic gauge widening were analyzed. The result shows that: the design concept of 'soft upper and rigid lower' can effectively decrease the vertical relative displacement of switch rail, and avoid the load of switch rail in advance, and ensure the safety of structure strength; It also could slow down dynamic gauge widening and serpentine movement amplitude, and improve the safety and stability of train; To ensure the safety of train, the design conception of soft upper and rigid lower should be applied for the subway switch.

Study on the Effect of Dynamic Wheel-Rail Contact Geometry Relationship in Turnout Region by the Track-Distance Roughness

Because of the complexity of turnout, the wheel-rail contact of turnout region is more complex than that of railway line. In order to study the wheel-rail contact Geometry relationship of turnout region, using cubic spline interpolation method to get the outline of control sections, the ideal wheel-rail contact relationship in turnout region was obtained by the means of trace line, and then analyze the effect of track-distance roughness on the dynamic wheel-rail Geometry contact, the result shows that appropriate gauge widening can improve the structure irregularity.