Locomotive Model Research Articles

The influence of semi-actively controlled magnetorheological bogie yaw dampers on the guiding behaviour of a railway vehicle in an S-curve: Simulation and on-track test

Many publications have shown that semi-actively controlled dampers could significantly improve the behaviour of a road or rail vehicle. In the case of a railway vehicle, these dampers promise to solve the contradiction between the damping requirements of different running modes (fast running on a straight track vs negotiating a tight curve). It is known that semi-active control of a bogie yaw damper can improve the vehicle behaviour when running fast on a straight track, but it is not known whether such semi-active control worsens the vehicle behaviour when negotiating a tight curve. This paper investigates the application of magnetorheological bogie yaw dampers in the locomotive bogie to reduce guiding forces and wear in wheel-rail contact when the vehicle negotiates the S-curve. The paper describes the magnetorheological damper, its mathematical model and the strategies for its semi-active control, followed by the results of simulations on a complex multi-body locomotive model and on-track testing on a real vehicle. The simulations and on-track tests have shown that the use of semi-active control of the yaw dampers reduces the guiding force by about 10%. The reduction in these forces will lead to a reduction in wear in the wheel-rail contact.

3D technologies in STEAM education

The article presents the application of 3D technologies in STEAM education through a conducted scientific research, highlighting the role of 3D modeling and 3D printing as an innovative approach in achieving an interdisciplinary learning model. The research included the following stages: preparation for designing a detailed 3D steam locomotive model; analysis of process difficulties; giving students and lecturers the opportunity to perform a specific modeling task, using basic primitives from solid geometry, as well as a questionnaire to analyze and evaluate the skills and knowledge of the participants in the 3D modeling field. In this context, the preparation process of a 3D steam locomotive model for educational purposes, using Autodesk 3ds Max software, is presented, and the 3D printing technology FDM is examined. We issued a challenge to the participants in the research to design a non-complex 3D model, using unfamiliar 3D modeling software Blender, within a limited time. The questionnaire covered topics in education, science, art, STEAM, and 3D modeling. The goal is to showcase the role of the integration of 3D technologies in educational environments with the idea of developing key skills and knowledge in learners.

Investigation of curve minimum radius in heavy-haul railway to improve wheel wear evolution and wheel-rail contact geometry

To determine the minimum and reasonable radius of horizontal curve for reducing wheel wear in heavy-haul railway design, a HXD locomotive with the wheel arrangement of C0-C0 is taken as the research object. Both the corresponding locomotive dynamic model and wheel wear model are established. Based on the measured wear data in a specific line, the simulation model is verified with the prediction error of wheel wear depth below 0.5 mm in general. The wheel wear evolution rules in 400∼1000m radius curves are studied and compared. The results indicate that, the wheel wear is large and sensitive to curve radius within 400∼600 m. The larger radius curve will be helpful to reduce wheel flange contact and wheel wear. For curve radius increasing from 600m to 1000m, the wheel average wear reduces slowly. Especially for curve radius below around 740 m, the wheel flange wear will be predominant. For radius above 740m, the wheel tread wear becomes the main wear form and the wheel flange wear can be reduced significantly. The increase of curve radius will also improve the wheel-rail equivalent conicity. If the minimum curve radius is set as 800m, the equivalent conicity difference between new wheelset and 1st ∼ 3rd worn wheelset can be kept below 21%, 52% and 9% respectively. In this case, the equivalent conicity is closest to the initial state and reaches a steady state, which will not change significantly with the radius further increasing. Viewed from the aspects of reducing wheel wear, avoiding wheel flange contact and keeping conicity stable simultaneously, the minimum radius of horizontal curve should be limited to 800 m. The research results validate the minimum curve radius suggested in Code for Design of Heavy-haul Railway in China, and provide a scientific explanation for the determination of this value.

Wheel-rail contact wear analysis on curved lubricated track for heavy haul locomotive studies

The effect of lubrications on a curved track to heavy-haul wheel-rail contact wear is studied. To analyse wheel-rail contact wear damage due to existing high-adhesive AC locomotive, a methodology for investigation is proposed, and the locomotive models are required to run at 20 km/h under maximum traction efforts, and the simulations include a DC locomotive for comparison. An extended creep force model, which was developed by Polach and has been widely used for the wheel-rail contacts under dry and wet conditions with variable friction coefficients, is further extended to apply for the typical low-coefficient-friction modifier, oil, and grease lubricant conditions. The wear models from two pairs of wheel-rail materials are used to predict the wear rates, and the wear numbers Tγ are presented for discussions. The simulations show that the lubricants significantly reduce the wheel-rail contact wear.

Suppression of carbody hunting for a locomotive caused by low wheel–rail contact conicity by optimising yaw damper location

This study addresses the issue of carbody hunting in an electric locomotive induced by low wheel-rail contact conicity. The main objective is to mitigate this unstable motion by optimising the location of yaw dampers while ensuring bogie stability under high conicity conditions. A field test was first conducted to observe the carbody hunting behaviour, and a detailed locomotive dynamics model was then developed and validated using experimental data. The impact of yaw damper locations on locomotive stability was investigated, taking into consideration different carbody modes. The findings reveal the mechanism behind the deterioration of carbody stability due to the yaw damper installation angle and two installation layouts were proposed to enhance the carbody stability. Comparisons were then made with traditional solutions using both linear and nonlinear analysis, and experimental validation confirmed the effectiveness of the optimised yaw damper locations in improving carbody stability. This research highlights the importance of optimising the yaw damper's location to suppress carbody hunting, providing valuable insights for railway engineers and offering a promising solution for enhancing stability in high-speed train.

Influence of the friction modelling decisions on the acceptance of the running behaviour of a friction-damped locomotive

Multibody simulations are widely used for the dynamic analysis of railway vehicles, including the acceptance of vehicle running behaviour. Among these, the freight vehicles have, generally, friction damped suspensions for which numerical modelling is particularly challenging due to the contacting geometries, the intermittent contact, and the frequent stick-slip transitions. The impact of modelling decisions of friction-damped suspensions on the acceptance quantities for vehicle behaviour is the focus of this work. The selection of friction models and tuning of their parameters is challenging. In particular, the selection of friction coefficients is not straight forward, as friction conditions vary during operation and over time. This work aims to address both problems. A model of a friction-damped freight locomotive is used to simulate the dynamic response of the vehicle under realistic operation conditions and assess the impact of the friction modelling decisions. The results show that the use of different friction models provides similar results if the parameters are appropriately tuned. In contrast, the selection of friction coefficients significantly impacts the acceptance quantities, with emphasis on the wheel-rail forces at small radius curve transitions. The results recommend that the standard should include variations of the friction coefficients used for the friction-damped suspensions.

Implementation of roughness and elastic-plastic behavior in a wheel-rail contact modeling for locomotive traction studies

All engineering surfaces are rough on the microscale, and the actual contact area is only a fraction of the geometrical area. Thus, it is essential to include roughness parameters in the model to simulate the real contact scenarios. An algorithm for the calculation of the realistic contact stresses with different surface roughness parameters considering elastic and plastic deformations and tribological behaviour at the wheel-rail interface was further developed and implemented in the wheel-rail coupling in the Gensys railway vehicle multibody software platform. Locomotive multibody model simulations using the developed wheel-rail coupling approach were performed under traction conditions that confirm the workability of the proposed algorithm by means of a comparison with results obtained with the original Extended CONTACT wheel-rail couplings under the same operational and simulation conditions. The results obtained allow an understanding of the difference in contact stress results between rough (Wheel Ra = 0.7 μm, Rail Ra = 0.4 μm) and ‘ideal’ (i.e., perfectly Smooth) contacts, and some limitations are stated in this paper.

Novel hybrid power system and energy management strategy for locomotives

The traditional fuel locomotive is the primary type of locomotive currently in operation on non-electrified railways; however, it presents certain disadvantages including a low efficiency and high fuel consumption. Therefore, in this study, a multimode hybrid locomotive configuration scheme is designed to improve the system efficiency and reduce fuel consumption during locomotive operation; further, the power flow state under different modes is analyzed, the mathematical model of the hybrid locomotive is established, and a system optimal efficiency calculation method is developed. Moreover, an energy management strategy based on the optimal system efficiency and with a hierarchical architecture is proposed. In the upper layer of this proposed energy management strategy, the optimal efficiency of all operating points and operational state of each component are determined offline using the optimal efficiency calculation method. The lower layer selects and coordinates the mode online by identifying the condition of the wheel and distributes the torque of each power source and the state of each transmission system component. The simulation results indicate that the fuel economy of the proposed energy management strategy is improved by 27.22% compared with that of the traditional fuel locomotive, and the fuel economy is only 7.21% lower than the global optimization result obtained via dynamic programming. In addition, no frequent clutch switching is observed under this strategy, and the electric motor does not operate under non-rated conditions for prolonged periods; these advantages ensure the rationality of control and the reliability of component operation. Finally, the results of a hardware-in-the-loop simulation test confirm that the proposed energy management strategy demonstrates good real-time performance.

Dynamic behavior of railway Vehicle-Ballasted track system with unsupported sleepers based on the hybrid DEM-MBD method

In order to understand dynamic effect of the unsupported sleepers on railway substructure at the meso-macroscopic scales, this paper develops a dynamics analysis framework combining the discrete element method (DEM) and the multi-body dynamics method (MBD). Firstly, a DEM model of ballasted tracks is built by the PFC software (The full name is Particle Flow Code, which is based on the general discrete element (DEM) framework and code software) for capturing meso-macro mechanical behavior, while a MBD model of electric locomotive is presented for simulating accurately dynamic wheel loads. A numerical simulation program is compiled by the FISH Language to implement two-way coupling calculation between the DEM model and the MBD model. Then, experimental validation is carried out by comparing the dynamic response results obtained from the ShuoHuang Heavy-haul Railway Line field dynamics test with the simulation results adopting a hybrid DEM-MBD model and the classical railway vehicle-track hybrid dynamics model (VTCD model) known as Zhai’s model. Finally, the hybrid DEM-MBD model is used to simulate dynamic responses of the locomotive and ballasted tracks considering 0 ∼ 5 pieces of unsupported sleepers. Simulated results show that the acceleration of 1st and 2nd wheelset begin to increase when running to the position of one sleeper-space in front of hanging area and increase to the maximum when running to the edge of hanging area. In addition, it is necessary to pay attention to the variation of acceleration amplitude near the characteristic frequency excited by the distance between bogie pivot centers. The contact stress in well-supported area adjacent to both ends of hanging area increases greatly when the number of unsupported sleepers is greater than 3.

Research on Operation Conflict of Auxiliary Transport Locomotive in Complex Mine Based on Extended Petri Net

Aiming at the operation conflict problem of multi-objective, multi-path and multi-vehicle relay during mine locomotive operation under complex geological conditions, a mine operation of locomotive modeling method based on an object-oriented stratified timed Petri net is proposed. In order to load and transport materials as object oriented, which are combined with the mine operation of locomotive rules and time constraints, stratified modeling of an underground roadway route is carried out. In addition, given token time parameters to describe the dynamic behavior of the locomotive, through the model to analyze the operation of a mine transport locomotive, the correlation matrix and accessibility tree analysis are used to study the conflict. Taking the actual operation of a locomotive in a complex mine in Guizhou as an example, the operation of locomotive behavior model was established to detect the interval and time of operation conflicts. The experimental results show that the proposed operation of locomotive modeling and conflict analysis method are effective and feasible, and have important application value to the safe operation of a mine production system.

A calculation and analysis of a cylindrical part of a steam boiler of a steam locomotive miniature model

The aim of this study is to calculate and analyze a cylindrical part of a steam boiler of a steam locomotive model. The cylindrical part of a steam boiler is the fundamental part of the steam boiler because it is designed to heat water and create steam using a large number (up to several hundred pieces) of boiler tubes passing through it, inside of which hot flue gases flow. Stress and reliability previous of the cylindrical part of the boiler were carried out using the methods of a theoretical analysis and the finite element method analysis.

Effect of drive and transmission system on wheel polygonal wear of an heavy-haul locomotive

Wheel polygonization intensifies the dynamic interaction between wheel and rail and reduces the service life of the locomotive and the rail system. The dynamic performance of the drive and transmission system (DATS) directly affects the wheel-rail interaction and further affects the wheel polygonization. In this study, a rigid-flexible locomotive coupled dynamics model of an HX locomotive is established. The DATS and the flexible characteristics of the wheelset are both considered. The calculation model of the wheel polygonal wear is established based on the local tangential contact distribution algorithm FaStrip and the USFD wear function. Effects of the DATS on the wheel-rail dynamic response and wheel polygonal wear are investigated. Evolution of the wear depth is studied under the different running speeds and the wheel profile initial states. The results indicate that the torsional vibration response of the DATS plays a significant role in promoting the development of the wheel polygonization. The more serious wear damage of the wheelset on the non-gear side (NGS) is both reflected in the actual service process and the numerically calculated results, which validates the established dynamics model and calculation method. This study could provide helpful reference for further understanding on the wheel polygonization phenomenon.

INEW method for experimental-numerical locomotive studies focused on rail wear prediction

Locomotive-track interaction is commonly represented by a complex mechanical system which is modelled in numerical studies. Numerical studies alone are not enough to precisely describe the behaviour of this mechanical system due to the various elements that can only be delivered from field and laboratory experimental programs. One such element is wheel-rail wear that has been found to contribute a considerable portion of the total cost of maintaining heavily used railway systems. Simulation studies are typically used for predicting wear of wheels and rails, but the majority of these do not consider in-train forces nor provide detailed modelling of traction and braking events and often rely on historic wear rates for comparable materials, reducing the accuracy of the wheel-rail volume loss estimation. This paper proposes a methodology for wear rate experimental measurements that allow improving the accuracy of wear analyses using dynamic simulations. The proposed method considers in-train forces by performing longitudinal train simulations whose results are then implemented on a detailed locomotive vehicle dynamic model with a traction mechatronic system co-simulation approach. The wheel-rail contact stress and slip results are then post-processed into a Dynamic Load Spectrum that contains contact stress and wheel slip occurrences. The Dynamic Load Spectrum was used to measure the wear rates for Australian AS60 head hardened rail steel material operating in combination with Class B wheel steel material. The experimental program delivered more realistic wear rates that correspond to actual industry operational scenarios. The measured wear rates were used to estimate the rail material volume loss for a specific train trip.

Evaluation of locomotive frame and fuel tank gusset modifications to prevent fatige cracks

Fatigue cracks have been detected in the underframes, fuel tanks, and fuel-tank gussets of some diesel locomotives that are currently in service. This presents the risk of a fuel tank separating from its locomotive and has an associated cost for making repeated repairs. It is therefore an interest to both operators of locomotives and to the designers of future locomotive models to understand the root cause of the cracks and to determine an effective remedy. In order to accomplish these goals, a finite element analysis (FEA) was used to identify events in the service environment that are capable of driving crack growth at a frequency that roughly matches the observed interval between crack repairs. These events were then used in further FEA simulations to predict the efficacy of various proposed remedies. It was found that the fuel tank, engine, and alternator of a locomotive behave as structural elements that resist deformations in the underframe. This explains why locomotive models with a relatively large fuel tank when compared to their engine and alternator are particularly susceptible to developing cracks: they experience higher stresses on their fuel tank and supporting brackets. It was also found that the most effective remedies were those that mitigate stress concentration effects from the gusset's rectangular design.

Modern approaches to the efficiency assessing of created vehicles

Introduction. The manufacturers currently develop new locomotives considering operating conditions with further locomotive fixation on the target ground. They also calculate the operational locomotive models with the key indicators for assessing the cost of the life cycle during the engineering stage. Therefore, the basic information for making operational decisions on purchase about selected locomotive items is the evaluation of the traction rolling stock effectiveness. The manufacturers of other vehicle types have similar aims in terms of operating conditions, engineering features, etc.Materials and methods. The scientists succeed in the usage of the modern evaluating approaches to the vehicles efficiency. The application of the similar criteria that differ in the calculation mechanism and the initial data volume is especially important in evaluating the effectiveness of the multimodal transportation of freight and passenger traffic. The article presented the critical analysis of the main approaches to assessing the effectiveness of the road, water and railway vehicles. Thus, the authors concluded that the manufacturers should consider both the efficiency of the vehicle and the usage intensity.Results. The authors demonstrate quantitative estimates of the proposed efficiency criterion for certificate features and considering real operational conditions. The paper presents the simulation results comparison with the calculation ones considering certificate features. Thus, operational conditions significantly effect the efficiency criterion.Discussion and conclusion. The authors highlight that the obtained results are universal for evaluating the effectiveness of the various vehicles in terms of different rolling stock features.

Problems, assumptions and solutions in locomotive design, traction and operational studies

Locomotive design is a highly complex task that requires the use of systems engineering that depends upon knowledge from a range of disciplines and is strongly oriented on how to design and manage complex systems that operate under a wide range of different train operational conditions on various types of tracks. Considering that field investigation programs for locomotive operational scenarios involve high costs and cause disruption of train operations on real railway networks and given recent developments in the rollingstock compliance standards in Australia and overseas that allow the assessment of some aspects of rail vehicle behaviour through computer simulations, a great number of multidisciplinary research studies have been performed and these can contribute to further improvement of a locomotive design technique by increasing the amount of computer-based studies. This paper was focused on the presentation of the all-important key components required for locomotive studies, starting from developing a realistic locomotive design model, its validation and further applications for train studies. The integration of all engineering disciplines is achieved by means of advanced simulation approaches that can incorporate existing AC and DC locomotive designs, hybrid locomotive designs, full locomotive traction system models, rail friction processes, the application of simplified and exact wheel-rail contact theories, wheel-rail wear and rolling contact fatigue, train dynamic behaviour and in-train forces, comprehensive track infrastructure details, and the use of co-simulation and parallel computing. The co-simulation and parallel computing approaches that have been implemented on Central Queensland University’s High-Performance Computing cluster for locomotive studies will be presented. The confidence in these approaches is based on specific validation procedures that include a locomotive model acceptance procedure and field test data. The problems and limitations presented in locomotive traction studies in the way they are conducted at the present time are summarised and discussed.

The methodology of a locomotive simulation model development within the model-oriented approach

The use of mathematical modelling at the early stages of product design makes it possible to substantiate fundamental technical solutions, taking into account all possible (large number) requirements for the product by consumers and operation. At this (early) stage, it is important to use well-tested and convenient tools for designers to create virtual stands and digital twins (DC), confirming compliance, as well as forming the structure of systems and products as a whole. The article discusses a comprehensive methodology for the process of constructing a numerical model of a locomotive for analysing dynamics under various operating conditions. It is based on the top-level structural model (LBM), which is presented in the form of a block diagram and is used at all stages of product design. The required detailing of such a model depends on the actual tasks. The detailed models of the systems that have been developed within the framework of the work are presented.

Locomotive Model for International Competitive Advantages Paths of High-Speed Railway Contractors

The high-speed railway (HSR) sector has been projected to experience exponential growth in the near future, and many HSR projects are being or will be implemented under international contracts. However, the huge international market also gives rise to fierce international competition. This study aims to explore the formation paths of international competitive advantages (ICAs) for HSR contractors. Through a comprehensive literature review, this paper firstly identified the 10 categories of 21 factors at the three covering levels (industry, firm, and project levels) that affect the ICAs of HSR contractors. The factors, categories, hypothetical paths model, and the preliminary questionnaire were refined and verified by the pilot study. Then the proposed paths model was verified through the methods of the partial least squares structural equation modeling and postsurvey interviews. The result validated the 10 significant ICAs paths (named the locomotive model), which could be further classified into two groups: the economic performance-oriented paths and the international reputation oriented paths. Moreover, the result showed the fundamental roles of the industrial triangle engine to the ICAs. This paper contributes to the competitive advantage theory in the field of international HSRs by proposing a verified locomotive model, which is important for the HSR practitioners to recognize in forming paths of ICAs and further developing their competitive strategic plans.

Influence of wheel-diameter difference of the same locomotive on ride quality of locomotive

The existence of wheel-diameter difference of track locomotive will directly affect the motion performance of locomotive. In this paper, the creep force of coaxial wheel-diameter difference is analysed, and the dynamic model of 2-axle bogie locomotive is established by SIMPACK software. Based on the study of two typical wheel-diameter difference of the same bogie, 10 special working conditions of wheel-diameter differences of the same locomotive are put forward. The effects of different working conditions and different wheel-diameter differences of the same working condition on the straight line motion performance of locomotive are analysed. The results show that, the lateral displacement and lateral ride quality index of locomotive body increase with the increase of wheel-diameter difference under the same working condition, and they do not exceed the safety limit. The change of wheel-diameter difference has little effect on the vertical ride quality index of locomotive body. According to the lateral displacement of the locomotive body, the 10 working conditions are divided into three grades. The third grade (working condition 4, working condition 5, working condition 8 and working condition 11) is more conducive to the safe and stable motion of the locomotive. Therefore, in the wheel matching installation and repairing process, priority should be given to the arrangement of wheel-diameter difference of the same locomotive in the third grade. This will provide a reference and basis for the scheme of locomotive wheel economic repairing.

Development and computational performance improvement of the wheel-rail coupling for heavy haul locomotive traction studies

Locomotive-track interaction is a multidimensional task because it goes in many directions depending on the aim of the investigation. One such direction relates to wheel or track damage produced by traction and braking of locomotives under different train operational scenarios. The best option for performing wheel or track damage studies is to use the Exact theory developed by Kalker directly in the simulation procedure to solve the contact mechanics task at the wheel-rail interface. In this paper, a specially developed wheel-rail coupling is presented based on the Extended Contact library and incorporated in a full mechatronic model of a modern heavy haul locomotive. The implementation of the parallel computing technique in the locomotive model development allows for achieving reasonable computational performance. Thereby, this complex approach shows a perspective for competing with the standard approach that uses a sequential computing technique or combined study approaches, while at the same time providing accurate results that are required for locomotive/track damage studies.