Rolling Stock Components Research Articles

Smart inspection of rail wheels with matrix arrays

Rail wheels are one of the most safety critical safety components of rolling stock. Any failure can lead to catastrophic events resulting in high material damage and personal injury or even fatalities. Therefore, international railway standards require non-destructive inspection by means of ultrasound testing (UT) on a regular basis. Due to increasing distances, loads and speeds there are increasing demands on the precision and the scope of testing. However, the inspection of train wheels is complicated due to the large variety of wheel geometries and the further influence of different milage. Moreover, extended inspection areas up to a full body inspection define many different defect positions, which are to some part difficult to access. This article describes industrial solutions, which allow the full-body inspection of train wheels including face, flange, web and tread for volumetric defects (from 2mm diameter) and surface cracks (from 5 mm length and 1 mm depth). In the latest upgrade, these systems can be now equipped with matrix probes. At the beginning of the article basic principles and general probe configurations will be discussed. The main part of this article is then dedicated to highlight the positive impact of the implementation of matrix probes. Besides a reduction of the form factor due to the decreased number of probes, matrix probes allow a direct coupling check thus fundamentally amending the existing state-of-the-art. Other advantages refer to improved settings for a higher reliability of the system. Finally, it is outlined in which way matrix probes provide additional functionalities to extend the current state-of-the-art towards a smart inspection.

Smart inspection of rail wheels with matrix arrays

Rail wheels are one of the most safety critical safety components of rolling stock. Any failure can lead to catastrophic events resulting in high material damage and personal injury or even fatalities. Therefore, international railway standards require non-destructive inspection by means of ultrasound testing (UT) on a regular basis. Due to increasing distances, loads and speeds there are increasing demands on the precision and the scope of testing. However, the inspection of train wheels is complicated due to the large variety of wheel geometries and the further influence of different milage. Moreover, extended inspection areas up to a full body inspection define many different defect positions, which are to some part difficult to access. This article describes industrial solutions, which allow the full-body inspection of train wheels including face, flange, web and tread for volumetric defects (from 2mm diameter) and surface cracks (from 5 mm length and 1 mm depth). In the latest upgrade, these systems can be now equipped with matrix probes. At the beginning of the article basic principles and general probe configurations will be discussed. The main part of this article is then dedicated to highlight the positive impact of the implementation of matrix probes. Besides a reduction of the form factor due to the decreased number of probes, matrix probes allow a direct coupling check thus fundamentally amending the existing state-of-the-art. Other advantages refer to improved settings for a higher reliability of the system. Finally, it is outlined in which way matrix probes provide additional functionalities to extend the current state-of-the-art towards a smart inspection.

A multi-scale gap-bridging CWE approach to windblown sand action on critical infrastructures: Modelling framework and case study on a high-speed railway line

Windblown sand action on critical infrastructures, such as high-speed railway lines, can completely inhibit their operation detrimentally affecting their safety and capacity. Several key components of the infrastructure are affected, among them the rolling stock material and infrastructure equipment. Computational Wind Engineering (CWE) is becoming more and more adopted during the different design stages to assess the impact of windblown sand. However, CWE-based analysis and design remain challenging because of the different scales involved in windblown sand transport starting from the full alignment scale (macro-scale), to the railway body (meso-scale), to the rolling stock (micro-scale). An innovative multi-scale modelling approach is proposed to bridge the gap between macro and micro scales involved in windblown sand processes, allowing to assess windblown sand action on key components. An exploratory case study addressing rolling stock operation in sandy environment along an high-speed railway line is analysed and discussed. This demonstrates the soundness of the approach in identifying most endangered railway segments, railway body sedimentation-prone areas and rolling stock components, and in quantifying windblown sand action at different scales. The proposed approach is well suited also to support the conceptual design of Sand Mitigation Measures.

Monotonic and Fatigue Behaviour of the 51CrV4 Steel with Application in Leaf Springs of Railway Rolling Stock

Leaf springs are components of railway rolling stock made of high-strength alloyed steel to resist loading and environmental conditions. Combining the geometric notches with the high surface roughness of its leaves, fatigue models based on local approaches might be more accurate than global ones. In this investigation, the monotonic and fatigue behaviour of 51CrV4 steel for application in leaf springs of railway rolling stock is analysed. Fatigue models based on strain-life and energy-life approaches are considered. Additionally, the transient and stabilised behaviours are analysed to evaluate the cyclic behaviour. Both cyclic elastoplastic and cyclic master curves are considered. Lastly, different fatigue fracture surfaces are analysed using SEM. As a result, the material properties and fatigue models can be applied further in either the design of leaf springs or in the mechanical designs of other components made of 51CrV4 steel.

Regulatory Framework for Ensuring Safe Operation of Railway Equipment Based on the Service Life of Load-Bearing Structures

Switching the operation of railway equipment to life cycle contracts and confirming its safety compliance with industry technical regulations in the absence of a legislative framework for the recall of substandard products entails the need for a more thorough analysis of resource indicators of structural components of rolling stock and track superstructure. From this point of view, the state of the existing regulatory framework for confirming the strength and service life criteria of load­bearing elements of rolling stock and track, the influence of the regulatory «guillotine» and the general transition from the system of Soviet state standards GOSTs and strength rules to modern approaches of certification and differentiation of such concepts as «standard» and «supporting standard».Trends in moving away from classical bench testing methods towards introduction of a resource-based approach with defectiveness assessment are shown using examples of previously carried out research on safe operation of ER200 bogie frame and on the transition to domestic cassette bearings as part of import substitution, currently carried out for different types of rolling stock.Based on the new methods and approaches, it is possible to consider longer periods of operation, reasonably assess the extension of service life, or introduce resource-restoring technology, ensuring further safe operation. As part of these new trends, a transition is being made to modern modelling methods for assessing product safety, concepts such as «virtual sensor» and «virtual train-track system» are being introduced. It is shown that a reasonable combination of full-scale operational tests and virtual digital modelling makes it possible to offer reliable estimates of service life and safety indicators at the design and operation stages in a short time.

도시철도 유지보수 운영에 IoT 도입 효과 분석

This study presents the IoT adoption policy analysis to estimate the benefit of redesigning the maintenance process in a predictive way for the Seoul Metro railway Line two. Accordingly, first, elicit five policy-level IoT deployment schemes for the rolling stock components. Secondly, five process change scenarios corresponding to each of the five schemes are redesigned for the depot maintenance operation. Thirdly, as per the industry-recommended IoT solution deployment analysis methods, simulation analyses using ARENA are conducted for each redesigned process. The simulation analysis assesses the incremental changes in the number of waiting trains for inspection, reduced maintenance manpower requirements, and reduced inspection time. Finally, with reference to the simulation results, the effect of alternative IoT deployment schemes is analyzed, and referenced to derive the plausible optimal level IoT deployment policy. The modelling and simulation procedures presented in this paper offer useful insights into the economic feasibility analysis of the IoT-embedded predictive maintenance area.

Ligthweigth (Talgo) high speed rodal frame. Composites in high responsability rail components

Nowadays, the railway sector demands new lighter designs in the structural components of rolling stock that compensate for its increase due to the incorporation of new technologies, to improve passenger comfort and experience, as well as to face new environmental challenges (reduction emissions, energy consumption, increased capacity, etc.). With this objective, Talgo introduces a frame in high-performance composite material (CFRP) in its rolling elements (wheels) for high-speed trains, traditionally made of metal (steel), which allows weight saving of over 45%. However, the introduction of new materials is subject to overcoming certain challenges: compliance with fire requirements, adaptation of existing regulations, ballast impact behavior, direct cost increase, etc. This project consists of different phases: a) design, in accordance with the requirements demanded by current standards, b) manufacture of prototypes, c) process of characterization and verification of properties of non-standard materials, d) testing of component validation equivalent to what is required of a conventional frame (static resistance and fatigue test up to 10 million cycles in accordance with existing regulations), and, finally, e) track tests.

Risk evaluation of failures of the running gear with effects on rail infrastructure

Preventive and corrective maintenance of the different components of rolling stock is mandatory to guarantee the safety of passengers and workers when using rail transport. Although different studies and models of degradation have been developed, the actual effect of rolling stock component defects in the infrastructure is not totally clear. From the different components of rolling stock, failures of elements of the running gear are more likely to cause track deterioration due to more severe wear wheel-rail interactions, producing undesirable effects on the infrastructure that can end in derailments.The aim of this paper is both to analyse through a failure modes and criticality analysis (FMECA) the different failure modes of the running gear and their effect on rail infrastructure and to analyse the prioritisation based on their criticality in order to give some insights into which components should receive special attention in maintenance procedures. Failures based on maintenance registers of passenger vehicles of railway companies involved in the Assets4Rail project were analysed. Results showed that defects related to wheels such as cracks, the movement of the wheel in the axle seat, failure of the axlebox bearing, or damage of the bogie frame are some of the failures with more severe consequences.

Анализ надежности узлов подвижного состава на основе эксплуатационных данных

Objective: To determine the most failure-prone rolling stock components and assemblies by processing statistical data obtained during operation using the classical reliability theory; to develop recommendations for maintaining the operational state of individual rolling stock components. Methods: Methods for calculating the quantitative reliability characteristics are used based on the rolling stock operational statistical data. Results: The 5-year operational data have been used to provide tabulated statistics on the failure rate of various rolling stock equipment. Reliability indicators have been calculated for various types of rolling stock equipment and the corresponding graphs have been plotted. Based on the calculations, the recommendations for the rolling stock maintenance have been developed. Practical importance: The calculations and the recommendations described determine the types of rolling stock equipment requiring more attention during maintenance

An Industry 4.0 Technology Implementation Model for Rolling Stock Maintenance

Railway operators are being challenged by increasing complexity and safeguarding the availability of passenger rolling stock, bringing maintenance and especially emerging technologies into the focus. This paper presents a model for selection and implementation of Industry 4.0 technologies in rolling stock maintenance. The model consists of different stages and considers the main components of rolling stock, the related appropriate maintenance strategies and Industry 4.0 technologies considering the maturity level of the railway operators. Relevant criteria and main prerequisites of the technologies were identified. The model proposes relevant activities and was validated by industry experts.

Feature Analysis of Degradation Signal of Rolling Stock Lateral Damper

The lateral damper is one of the key components of rolling stock. Establishing the relationship between the degraded signal and the health state of the lateral damper is important in order to perform timely performance detection and fault diagnosis. This paper proposes a wavelet packet cross-correlation method (WPCC) that is based on wavelet packet transform (WPT) and cross-correlation analysis (CCA). First, the vibration signals under different running speeds, different running conditions, and different track excitations were collected and analyzed. Second, the wavelet packet transform was used to select larger energy band signals for reconstruction. Subsequently, the WPCC coefficient was calculated between the reference signal and the signal to be measured. The proposed method was applied to analysis of vibration signals of the lateral damper performance degradation. The lateral damper health condition was divided into four intervals, and the average accuracy calculated under different running speeds, different running conditions, and different track excitation was 95%.

Comprehensive method for evaluating results of ultrasonic testing of parts and components of rolling stock when adjusting the sensitivity for different reflectors

Operation of railway rolling stock is accompanied by high costs of maintaining its operating condition throughout the entire period of operation. To improve the operation efficiency of rolling stock, methods and diagnostics tools have been developed, which are used both in its manufacture and in carrying out maintenance and repairs, and as an independent technological process. Diagnostics allows to increase the availability factor and the probability of uptime of the rolling stock, reduce the complexity and cost of periodic maintenance of its nodes. The article proposes a new integrated method for estimating discontinuities in parts and units of railway rolling stock according to the amplitude — distance — diameter diagrams by the standardless method with the possibility of determining the type of discontinuity by the dual-frequency method of flaw-detection with a manual ultrasonic testing with a single-channel ultrasonic flaw detector. Developed method is most relevant in the control of cast parts of railway rolling stock, since castings can be equally likely to contain bulk (pores, shells, nonmetallic inclusions, etc.) and planar discontinuities (cracks of different origin; flocks; segregations that lead to violation continuity, etc.). Proposed method allows estimating the discontinuity by comparing the amplitude of the echo signal from it with the corresponding type of tuning reflector: if the discontinuity is planar as a result of using the two-frequency flaw-detection method, the comparison is carried out with the amplitude of the flat-bottomed cylindrical reflector; if the discontinuity is volumetric, then the comparison is made with the amplitude from the spherical reflector. The article describes the algorithm that was developed to automate the calculation of the parameters of the amplitude — distance — diameter diagram, the parameters of the use of the two-frequency method, and also the estimation of the detected discontinuities, and, based on it, the NDTRT-25 software that allows ensuring the convenience of the operator-diagnostician.

A risk-based modelling approach to maintenance optimization of railway rolling stock

Purpose Railway transport maintenance plays an important role in delivering safe, reliable and competitive transport services. An appropriate maintenance strategy not only reduces the assets’ lifecycle cost, but also will ensure high standards of safety and comfort for rail passengers and workers. In recent years, the majority of studies have been focused on the application of risk-based tools and techniques to maintenance decision making of railway infrastructure assets (such as tracks, bridges, etc.). The purpose of this paper is to present a risk-based modeling approach for the inspection and maintenance optimization of railway rolling stock components. Design/methodology/approach All the “potential failure modes and root causes” related to rolling stock systems are identified from an extensive literature review followed by an expert’s panel assessment. The failure causes are categorized into six groups of electrical faults, structural damages, functional failures, degradation, human errors and natural (external) hazards. Stochastic models are then proposed to estimate the likelihood (probability) of occurrence of a failure in the rolling stock system. The consequences of failures are also modeled by an “inflated cost function” that involves safety-related costs, corrective maintenance and renewal (M&R) costs, the penalty charges due to train delays or service interruptions as well as the costs associated with loss of reputation (or loss of fares) in the case of trip cancellation. Lastly, a time-varying risk-cost function is formulated to determine the optimal frequency of preventive inspection and maintenance actions for rolling stock components. Findings For the purpose of clearly illustrating the proposed risk-based inspection and maintenance modeling methodology, a case study of the Class 380 train’s pantograph system from a Scottish train operating company is provided. The results indicate that the proposed model has a substantial potential to reduce the M&R costs while ensuring a higher level of safety and service quality compared to the currently used inspection methodologies. Practical implications The railway rolling stocks should be regularly inspected and maintained so as to ensure network availability and reliability, passenger safety and comfort, and operations efficiency. Despite the best efforts of the maintenance staff, it is reported that a considerable amount of maintenance resources (e.g. budget, time, manpower) is wasted due to insufficiency or inefficiency of current periodic M&R interventions. The model presented in this paper helps the maintenance engineers to assess the current maintenance practices and propose or initiate improvement actions when needed. Originality/value There are few studies investigating the application of risk-based tools and techniques to inspection and maintenance decision making of railway rolling stock components. This paper presents a modeling approach aimed at planning the preventive repair and maintenance interventions for rolling stock components based on risk measures. The author’s model is also capable of incorporating real measurement information gathered at each inspection epoch to update future inspection plans.

The Influence of High-Frequency Cyclic Loading on the Mechanical Properties of Steel

The modern development of high-speed transport causes a requirement toughening of the safety requirements for rolling stock and upper track components. Researchers and constructors are actively working towards the creation of more complete and adequate models of constructers and their elements, as well as new materials for their manufacture. The problem of studying traditional materials in various modes of rolling stock operation, including increasing the frequencies of dynamic influences and imposing effects from various loads and oscillations to the high-frequency area, becomes relevant and timely. This work is devoted to modeling the influence of high-frequency loading on a sample made of rail steel, this kind of influence takes place when rolling stock passes through an artificial constructer. It is assumed that the work of the rail within the sleepers step is described by the laws of uniaxial tension-compression. Experimental results and conclusions on ultrasonic high-frequency cyclic tests and structural analysis of the model material - low-carbon steel of the perlite class are presented.

Improving the energy efficiency of operation of elements of the structures of the rolling stock by means of surface engineering.

The manufacture of rolling stock components with a given life cycle based on the computerization of all design and production stages is the most promising way to increase the energy efficiency of its operation. The implementation of this approach requires the expansion of the use of technologies that provide parts with a high level of mechanical and operational properties. The state of the surface layers is important in the formation of the reliability parameters of high-loaded parts. The principles of using system approaches for the physical justification of the choice of the optimal modes of engineering grain boundaries depending on the operating conditions of products are presented. New approaches and algorithms have been created that allow quantitative and qualitative studies of the effect of technological treatments and the chemical composition of polycrystals on the strength of grain boundaries and the processes of softening of the boundary zones. Using the developed techniques, the ways to control the energy state of the internal interfaces by doping, microalloying and heat treatment were determined to increase the resistance to brittle fracture and wear of the steels used in the manufacture and repair of rolling stock.

Studies Concerning the Microstructure and Hardness Obtained After the Heat Treatment Applied to Steels Used for Components of Rolling Stock

This paper proposes a study on the influence of the hardening and annealing thermal treatments applied on two types of steels used for rolling stock. There is a type of analysis in two ways, according to the thermal furnace used for the applied treatments. The results obtained demonstrate the low wear of the rolling stock components.

INVESTIGATION OF PREMATURE DESTRUCTION CAUSES OF LOCOMOTIVE 2TE116 CRANKSHAFT

Purpose. The work is aimed at identifyinbg the causes of premature destruction of the locomotive 2TE116 crankshaft. Methodology. Macrostructural, fractographic, and analytical analyses have been used to identify the causes of premature destruction of the shaft. Findings. In this work, the subject of the study is not only the structural state and properties of the shaft material, but also the chemical properties of the environment, the working fluid and the state of the working documentation for the locomotive operation. The research carried out in the work showed: 1) the non-conformity of the impact viscosity of the crankshaft material to the requirements of the relevant standard; 2) the presence of more than 17% of diesel fuel in the chemical composition of oil, which significantly increases the friction coefficient in the working mechanism due to the formation of carbon deposit, the areas of adhesion and pitting corrosion of the metal. Originality. A comprehensive analytical and technical approach for identification of premature destruction causes of the locomotive 2TE116 crankshaft was used in the work. The maximum number of factors that could influence the premature destruction of the crankshaft were estimated. It was shown that the combination of factors that negatively influenced the performance characteristics of the crankshaft has reached the so-called «critical mass», which inevitably caused the destruction. Introduction of additional signaling factors (in addition to the noise factor during the operation of the diesel engine with oil contaminated by diesel fuel more than 17%) and fault monitoring in the operation of such large mechanical aggregates will additionally discipline locomotive drivers and mechanics when working on instructions for warning destruction of large locomotive structures. Practical value. The studies confirmed the importance of controlling the chemical composition and mechanical characteristics of rolling stock components and constructions. The need for periodic control of the oil chemical composition is shown. Supervision over the careful keeping of work book can prevent the destruction of valuable structures of rolling stock.

THEORETICAL BASIS OF PARAMETRIC SYNTHESIS FOR CARRYING SYSTEMS OF CARS

Purpose. The article is aimed to systematize and structure representation of theoretical grounds for the optimization designing of railway car components and practical ways of its implementation. Methodology. The study is based on analysis of several well-known articles on the subject, as well as on authors' researches, some mathematical foundations and computer modeling. The rolling stock components structural analysis was made by applying modern and acknowledged methods. Findings. In the study the authors systematized the set of methodological approaches to the freight car design processes; they also analyzed every application phase of the designing process and its conditions. The article presents the developed mathematical model of the car component implementation. This model takes into account all the calculated cases of the car life cycle. Moreover, the model also can be applied to other transport modes accounting their specific operation modes. The possibility to generate different construction options for equally strong car component with minimum material intensity was also shown in the article. There were several methods developed for finding optimal solutions that make it possible to calculate the sought characteristics of construction elements with the reliable accuracy. The presented variety of different approaches significantly extends engineering apparatus by increasing the synthesis and analysis abilities of the car design. Originality. The authors proposed the methodological foundations of the car components design aimed at creating their optimal structural parameter execution and the operating features based on the results of the detailed research. Practical value. Expediency and effectiveness of the presented methods has been confirmed by positive experience of its application when constructing the general-purpose gondola cars, models 12-9904 and 12-9904-01, as well as when upgrading existing constructions of freight cars, model 12-9745 and the hoper car 20-9749.

Impact of maintenance conditions of vehicle components on the vehicle–track interaction loads

To improve the efficiency and competitiveness of railway transport, passenger and freight trains should travel faster and have increased payload, without losing the necessary levels of running safety and ride comfort, as well as assuring low aggressiveness on track and minimising the life cycle costs. Hence, the manufacturer’s challenge consists of improving the dynamic performance of the railway vehicles and reducing the loads on the track as well as on the rolling stock components. These objectives can be achieved through optimizing the design of the vehicle, while taking into consideration that the characteristics of the vehicle and of the track may change over time and space, and that they depend on the maintenance conditions of the vehicle and of the infrastructure. This work proposes a computational methodology to study how the varying vehicle component characteristics, on normal and degraded conditions, impact on the vehicle/track interaction loads and on the track damage. The purpose of this study is to trace a path towards a realistic definition of a load mission profile for the structural fatigue dimensioning of the vehicle components. The assessment criteria and the evaluated quantities are defined according to the EN14363 regulation.

Risk Evaluation of Railway Rolling Stock Failures Using FMECA Technique: A Case Study of Passenger Door System

Railway transport consists of two main asset classes of infrastructure and rolling stock. To date, there has been a great deal of interest in the study and analysis of failure mechanisms for railway infrastructure assets, e.g. tracks, sleepers, bridges, signalling system, electrical units, etc. However, few attempts have been made by researchers to develop failure criticality assessment models for rolling stock components. A rolling stock failure may cause delays and disruptions to transport services or even result in catastrophic derailment accidents. In this paper, the potential risks of unexpected failures occurring in rolling stock are identified, analysed and evaluated using a failure mode, effects and criticality analysis-based approach. The most critical failure modes in the system with respect to both reliability and economic criteria are reviewed, the levels of failure criticality are determined and possible methods for mitigation are provided. For the purpose of illustrating the risk evaluation methodology, a case study of the Class 380 train’s door system operating on Scotland’s railway network is provided and the results are discussed. The data required for the study are partly collected from the literature and unpublished sources and partly gathered from the maintenance management information system available in the company. The results of this study can be used not only for assessing the performance of current maintenance practices, but also to plan a cost-effective preventive maintenance (PM) programme for different components of rolling stock.