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Abrasive Waterjet (AWJ) milling effectively processes high-strength materials like WNiFe tungsten alloy without altering their properties. This study investigates the effects of jet pressure, traverse speed, and abrasive mass flow rate on the machining performance. The results indicate that increasing jet pressure significantly enhances groove depth, with higher pressures leading to more aggressive material removal. Conversely, higher traverse speeds reduce groove depth, emphasizing the need for slower speeds for deeper penetration. Increased abrasive mass flow rates also significantly improve groove depth but pose challenges related to material wear and cost. Surface analysis using scanning electron microscopy (SEM) revealed that higher jet pressures and lower traverse speeds produce smoother surfaces and more distinct grooves. The findings highlight the importance of optimizing AWJ parameters to achieve efficient material removal and desired groove geometries. This research provides valuable insights for improving AWJ machining of tungsten alloys in industrial applications. [ABSTRACT FROM AUTHOR]

This paper presents a systematic literature survey on diagnostic methods used for railway materials and systems. The authors analyze various railway accident reports, focusing on the types of failures described and their causes. Previous review papers have addressed various aspects of railway systems diagnostics; however, most of the existing research focuses on specific parts of the rail vehicle or subsystems. In contrast, this survey focuses on railway diagnostic systems rather than general diagnostic methods used in mechanical and electrical engineering. The authors classify the types of failures and diagnostic methods that are used in rail transport into two categories: infrastructure and rolling stock. The purpose of this paper is to systematize the types of failure that occur in railway transport systems; identify the state-of-the-art means and methods of diagnostics in railway materials and systems, with particular focus on new research findings; and identify trends and possible research gaps in need of further development. [ABSTRACT FROM AUTHOR]

Components made of composite materials are being increasingly used in the construction of rolling stock. Currently, the use of components made of composite materials as train structural elements is increasingly being considered. Non-structural components made of composites are most often found inside rail vehicles (e.g., the interior lining), while structural components made of sandwich composite materials can be used for the roof, sidewalls, and underframe constructions. This article provides a description of an innovative sandwich composite developed for a metro's underframe, as well as the production process and preparation of the composite specimens. The main parts of the work are flammability and mechanical (static and fatigue) tests of the innovative sandwich composite. The scope of the flammability tests included the testing of the fire properties using the radial plate method, the optical density of smoke, and the content of toxic gases. The mechanical strength of the sandwich composite was examined during a flexural (three-point bending) test and a fatigue strength under a given dynamic load. The results presented in the article are very significant, both in terms of flammability and the mechanical strength tests. In order to produce large-size train components, appropriately large patches of component layers of the composite are required; this may pose production problems. [ABSTRACT FROM AUTHOR]

To ensure the operational safety of the automatic couplers of a rolling stock subjected to cyclic loading, reliability and residual service life must be determined. This paper involved the prediction of the durability of the automatic coupler SA3 by analytical summation of cyclic damage. During the investigation, the cyclic characteristics and damage modes of the automatic coupler material that influence the accumulation of damage are determined. The stress and strain state assessment model was developed using a 3D finite element method for the automatic coupler housing as a geometrically complex component. A methodology was used to assess damage per load cycle that is applicable to any sequence of automatic coupler load cycles. For this purpose, the authors used low-cycle stationary load dependencies that account for quasi-static and low-cycle fatigue damage. The investigation showed that a coupler may develop a crack due to accumulated quasi-static and fatigue damage. For damage summation, the dependences of low-cycle stationary stress-controlled load accounting for low-cycle, quasi-static fatigue damage are proposed in view of the variation of the load on the automatic coupler during operation depending on the weight of the rolling stock, velocity, and railway relief. The proposed methodology is applicable to the calculation of other housings under similar loading conditions. [ABSTRACT FROM AUTHOR]

Hybridized vehicular power supply (HVPS) are acquiring widespread adoption in various applications such as providing power for passenger or heavy‐duty electric vehicles, more‐electric ships, electrified rolling stocks, and more. Stability analysis is a critical issue for HVPS, but it presents significant challenges due to their prominent high‐dimensional and nonlinear characteristics. This paper presents a large‐signal stability analysis scheme for HVPS of rolling stocks, enabling the assessment of system stability under sudden load changes. Based on the state‐space averaging method, a mathematical model for the large‐signal behavior of the system is established. Subsequently, the small‐signal stability parameter range of the system is determined by analyzing the eigenvalues of the Jacobian matrix. To further analyze the stability of the system during large‐signal disturbances, a nonlinear decoupling transformation approach is employed to decompose the original high‐order state equations into multiple lower‐order equations. For the decoupled lower‐order subsystems, their stability is analyzed using phase portrait, and the region of attraction (ROA) is determined using the inverse trajectory method. Based on the stability analysis results, the controller is enhanced to bring the points outside the ROA back within it, thereby mitigating the transient instability phenomenon of the system. The effectiveness of the proposed method was demonstrated using two case studies. [ABSTRACT FROM AUTHOR]

The object of research is a pneumatic spring of high-speed rolling stock of the railway. The method of experimental static testing of a pneumatic spring of high-speed rolling stock is presented. Based on experimental tests, the "force-strain" dependences of a pneumatic spring are obtained when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm. Using a thermodynamic model, a quadratic equation is found to determine the effective area of a pneumatic spring. It is established that when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm the effective area of the pneumatic spring varies from 0.231 m2 to 0.306 m2. The scientific novelty lies in the fact that for the first time, on the basis of static experiments, the change in the effective area of the pneumatic spring of high-speed rolling stock depending on the value of the gauge pressure in the spring was established. This will make it possible to determine the forces acting on the pneumatic spring in different operating conditions, ensuring the required level of safety of rolling stock. [ABSTRACT FROM AUTHOR]

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Purpose. To justify the need to apply the “principle of adequacy of probabilities” as a measure to improve the risk management methodology, to prevent (counteract) existing and emerging risks (threats) to the security of complex systems. Methodology. The well-known methodological principle called “Ockam’s Razor” was used. In the course of the research, a complex method was used, which included formal and logical analysis of normative and scientific and technical literature, analysis of statistical data, synthesis, abstraction, experiment, observation, generalization of data, description. Findings. In the course of the research, one of the threats (danger, risk) was identified, which simultaneously affects the existence of such a system due to traffic safety of rolling stock of rail transport enterprises, and the full implementation of the system’s capabilities due to axle loads, mass and speed movement of rolling stock, level of operating costs, passenger flow, regularity of transportation, etc. Experimental application of the lubricant “Mariol NT” in SPP 12-5, GS-3 lubrication systems showed a decrease in wear intensity by 240 %. Due to the use of a new lubricating material applied to the friction surface of wheel rims as part of the paint coating, the wear intensity of flanges of twin-wheel rims is reduced by 2.2 times, and that of locomotives by 2.4 times. Originality. It was determined that the “principle of adequacy of probabilities” as a measure of improvement of the risk management methodology, prevention (counteraction) of existing and prospective risks (threats, dangers) during the safety assessment of complex systems is currently not applied, but its consideration helps to prevent (countermeasures) to existing and emerging risks (threats) to the safety of complex systems. Practical value. The use of the “principle of adequacy of probabilities” allows for the theoretical and experimental determination of the numerical value of the ratio between the probability of an event occurring, caused by the action of an identified threat that negatively affects the state (level) of safety and operability of system elements at all stages of its existence, and the probability of a positively compensatory effect of the developed countermeasure to the identified threat. [ABSTRACT FROM AUTHOR]

Purpose. To analyze the energy saving reserves under the conditions of implementation and integration of the system in order to find rational driving modes in the general system of managing underground electrified transport. Methodology. The work presents the method for processing data arrays obtained experimentally with the help of a measuring system and theoretically with the use of the “Rational Trajectory” software. Findings. Experimental studies were carried out using a testing system created on the basis of a refurbished train with energy recovery system. Theoretical studies were carried out using the “Rational Trajectory” software, which is based on the principle of solving a multi-criteria problem by the method of the main criterion. The minimum amount of electricity consumption from the overhead contact line was chosen as the main criterion. The software was developed in the LabVIEW graphical programming environment in order to determine the rational modes of driving rolling stock and energy indicators in a given area of its operation. The amount of electricity consumed for traction and the amount of electricity generated by the train during regenerative braking were determined based on the results of experimental and theoretical studies, respectively, under typical and rational modes of driving the train for given identical operating conditions. Originality. Further research on the analysis of energy saving reserves on the rolling stock of underground electrified transport was achieved due to the introduction of a system for finding a rational driving mode. Practical value. It has been established that the implementation and incorporation of the “Rational Trajectory” software into the train control system will save up to 14.7 % of the amount of electricity consumed for traction, compared to typical modes operation on a given track section. [ABSTRACT FROM AUTHOR]

East Japan Railway Company (JR East) is aiming to "realize driverless train operation" as one of the key measures to respond to rapid changes in the business environment. Currently, Automatic Train Operation (ATO) equipment is not installed on the Shinkansen, but there are plans to introduce ATO or driverless operation in the near future. From 2018-2021, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) held the "ATO Technology Study Group for Railways" in which the concept of technical requirements necessary for driverless operation was discussed. In 2021, JR East conducted the GOA4 demonstration test on the Joetsu Shinkansen. In this test, we were able to confirm the basic functions of Shinkansen vehicles such as automatic departure control, speed control, fixed position stop control, and remote stop control using ATO. We aim to realize unattended operation (GOA4) for deadhead trains between Niigata Station and the Niigata Shinkansen Rolling Stock Center by the end of the 2020 s, and driverless operation (GOA3) for passenger trains of the Joetsu Shinkansen by the mid-2030s and continue to develop the necessary technologies and build systems. [ABSTRACT FROM AUTHOR]

Purpose. The paper aims to investigate the increase of fuel efficiency of a mainline freight locomotive in the case of separate loading of diesel generators of its individual sections. Methodology. The study was carried out for the non-electrified section between Kharkiv-Sorting and Sumy stations during the movement of a freight train with 45 loaded and empty freight cars in both directions. The movement of a train with a freight mainline two-section diesel locomotive 2TE116 was taken. To determine the parameters of the movement, a mathematical model was developed, which was used to solve a series of traction problems. The traction problems are calculated for the cases of train movement with a series diesel locomotive and a diesel locomotive with separate loading of diesel generators of its individual sections. A method of loading sections is proposed for modeling and the traction characteristics of the locomotive are constructed in accordance with this method. Findings. It has been established that the use of separate loading of diesel generators of individual sections of a diesel locomotive when running a train with loaded cars reduces fuel consumption by 18.7...19.6 % compared to running a serial diesel locomotive. For the case of a train with empty cars, the reduction in fuel consumption is 8.1...10.3 % compared to a train with a serial diesel locomotive. It has been found that the movement of a train with empty cars can be carried out with traction by one section of a diesel locomotive. In this case, the reduction in fuel consumption is 29.5...31.0 %. In all the studied cases, the duration of the movement is practically the same. Originality. The authors of this paper have solved traction problems for a real track section when a train with a freight diesel locomotive is moving, where separate loading of diesel generators of its sections is used. A method for forming the traction characteristics of a locomotive with separate loading of diesel generators is proposed. Practical value. The developed mathematical models of train movement, including for the case of separate loading of diesel generators of diesel locomotive sections, can be used in the modernization of diesel locomotives or the creation of diesel rolling stock using a multi-diesel power plant.

The relevance of this study lies in the fact that motor transport services of federal ministries and departments of the Russian Federation, agencies subordinate to them, law enforcement and supervisory authorities are carried out by departmental road transport. The operation of departmental road transport in modern conditions is based on documents developed for public road transport. In some cases, departmental acts on the organization of the work of vehicles and personnel in relation to the functions and tasks of the relevant department are not systematically used. The operation of departmental road transport is characterized by excessive dispersion of regional production and technical bases for the maintenance, maintenance and repair of a specialized fleet, as a rule, assigned to individual institutions. As a result, more material and technical resources, rolling stock and personnel are involved in the transportation process of departmental road transport than at public road transport. Increasing the efficiency of departmental road transport consists in the consolidation and centralization of regional production and technical bases, as well as in rationing the resource provision of the transport process. The subject of the study is the regularities of the functioning of the production and technical bases units of the departmental structure. The purpose of this study is to increase the efficiency of departmental road transport operation due to the territorial integration of production and technical bases. To achieve this goal, it is necessary to solve a number of tasks, the specifics of which are determined by the features of a specialized departmental road transport on the example of the divisions of the regional Department of the Federal Penitentiary Service for the Rostov region, concluded: a) in the collection, grouping and processing of statistical information from divisions by type, model, number and costs of operation and performance of transportation in the field of transport by specialized rolling stock; b) determination by geographical coordinates of the location of divisions in the region; c) the compilation of an adjacent matrix of distances between divisions. The methodology of the study includes a methodology for the territorial integration of production and technical bases of regional units of departmental road transport based on the «center of gravity» method, taking into account the costs of operating a specialized fleet and determining the head production and technical bases. The obtained research results can be used for other departments, divisions, organizations and services of departmental structures in which a specialized fleet is involved.

This paper analyzes the current situation of interval train control systems (railway interlocking) on the railway network of Kazakhstan, geared towards enhancing the effectiveness of railway transportation, the objective is to augment the capacity of rail lines, diminish operational expenses, minimize energy consumption, and mitigate wear on both tracks and rolling stock. To evaluate the data transmission channel of the TETRA standard, a test model with a long ping and a load test has been developed, and a two–stage test methodology has been proposed for the Zhetygen – Altynkol section. According to the results of the conducted experiments, it is proved that if the connection is lost for more than 60 seconds, the train automatically stops with an emergency braking command and, subject to the restoration of data transmission between the OBU (onboard unit) and the modem, the radio-blocking system works normally for cases with loss of communication and the board permits to move. For evaluating the influence of deploying radio communication on radio-blocking and signal strength, the Hata model within the COST231 framework was chosen. This model incorporates diverse factors contingent upon the environment, such as urban or suburban settings. The model of path loss «Loss of suburban macro-path» was chosen as a model. [ABSTRACT FROM AUTHOR]

The paper describes the existing technologies and challenges associated with galvanized metal production at the Novolipetsk Steel (NLMK) plant. Possible ways to improve the process using machine-learning tools are proposed. [ABSTRACT FROM AUTHOR]

Estimating line impedance is relevant in transmission and distribution networks, in particular for planning and control. The large number of deployed PMUs has fostered the use of passive indirect methods based on network model identification. Electrified railways are a particular example of a distribution network, with moving highly dynamic loads, that would benefit from line impedance information for energy efficiency and optimization purposes, but for which many of the methods used in industrial applications cannot be directly applied. The estimate is carried out onboard using a passive method in a single-point perspective, suitable for implementation with energy metering onboard equipment. A comparison of two methods is carried out based on the non-linear least mean squares (LMS) optimization of an over-determined system of equations and on the auto- and cross-spectra of the pantograph voltage and current. The methods are checked preliminarily with a simulated synthetic network, showing good accuracy, within 5%. They are then applied to measured data over a 20 min run over the Swiss  16.7  Hz railway network. Both methods are suitable to track network impedance in real time during the train journey; but with suitable checks on the significance of the pantograph current and on the values of the coefficient of determination, the LMS method seems more reliable with predictable behavior. [ABSTRACT FROM AUTHOR]

Adequate vertical track support is essential for safe and efficient railway operations. Insufficient support leads to distorted track geometry, increased dynamic loads, component stress, poor ride quality, rolling stock damage, and derailment risks. Current inspection practices focus on assessing the condition of the track components and geometry, rather than the root causes of degradation. To improve this condition, this study presents the use of a methodology that utilizes an autonomous vertical track deflection measurement system mounted on a loaded rail car (36 tonnes/axle) to support track maintenance decisions in a heavy haul railroad located in southeast Brazil. The system continuously measured substructure stiffness along the railway line. Over one year, data were collected from over 8000 km of track. The study highlighted seasonal effects on track degradation over time, identifying areas with significant deflections and high deflection rates, which contribute to issues such as differential settlement and reduced lifespan of track components. Additionally, the study revealed seasonal effects, with deflections peaking during wet weather and decreasing during dry cycles. A method to classify weak track areas was developed, facilitating monitoring and enabling more effective maintenance planning, contributing to the reduction of overall track maintenance costs and enhancing safety and operational efficiency. [ABSTRACT FROM AUTHOR]

The railway system is a complex technical system-of-systems (SoS). To address the complexity of the railway system, a holistic approach is needed that facilitates the development of an appropriate asset management regime. A systems-of-systems (SoS) approach considers the complex nature of the railway system, comprising interconnected subsystems like rolling stock and infrastructure. Neglecting these interdependencies risks sub-optimization of the overall system performance. Asset management of the railway system utilising a SoS approach ensures the focus of asset management on overall system requirements. The efficiency and effectiveness of the railway system is based on aspects such as availability, reliability, and safety performance. To enhance these aspects, monitoring, and improvement of key performance indicators (KPIs) emphasizing increased capacity and reduced operational costs is essential. The KPIs offer quantifiable parameters for performance optimization. Augmenting asset management through data-driven technologies can improve the efficiency and effectiveness of asset management. However, challenges persist in the implementation of data-driven solutions due to the railway system's complexity and lack of a holistic perspective. A systematic performance-driven framework with a system-of-systems approach for augmented asset management of railway system provides handrail for the utilisation of data-driven technologies with railway system requirements at the centre while developing an asset management regime. The proposed framework aims to establish a clear relationship between system KPIs, and the performance of sub-systems and components aiding railway organizations in asset management design and implementation. This paper explains the important components of the proposed framework and demonstrates the application the framework for asset management and maintenance planning of high value components in the fleet of railway rolling stock. Adoption of the proposed framework is expected to enhance asset management through development and implementation of data-driven solutions that are aligned with system KPIs, to support asset management decision making. [ABSTRACT FROM AUTHOR]

This paper presents a deep learning approach for predicting rail corrugation based on on-board rolling-stock vertical acceleration and forward velocity measurements using One-Dimensional Convolutional Neural Networks (CNN-1D). The model's performance is examined in a 1:10 scale railway system at two different forward velocities. During both the training and test stages, the CNN-1D produced results with mean absolute percentage errors of less than 5% for both forward velocities, confirming its ability to reproduce the corrugation profile based on real-time acceleration and forward velocity measurements. Moreover, by using a Gradient-weighted Class Activation Mapping (Grad-CAM) technique, it is shown that the CNN-1D can distinguish various regions, including the transition from damaged to undamaged regions and one-sided or two-sided corrugated regions, while predicting corrugation. In summary, the results of this study reveal the potential of data-driven techniques such as CNN-1D in predicting rails' corrugation using online data from the dynamics of the rolling-stock, which can lead to more reliable and efficient maintenance and repair of railways. [ABSTRACT FROM AUTHOR]

The demonstration of compliance of rolling stock against disturbance limits for railway signaling, and in particular track circuits, is subject to a large deal of variability, caused by the diverse values of the electrical parameters of the railway line and resulting transfer functions, as well as the operating conditions of the rolling stock during tests. Instrumental uncertainty is evaluated with a type B approach and shown to be much less than the experimental variability. Repeated test runs in acceleration, coasting, cruising, and braking conditions are considered, deriving both max-hold (spread) and sample (or experimental) standard deviation curves compared to the respective mean values (type A approach to the evaluation of uncertainty, as defined in of the Guide to the Uncertainty in Measurement. The major source of variability affecting a significant portion of the spectrum is caused by the superposed oscillations of the onboard LC filter, for which different choices of the transformation window duration are discussed. The test runs and the acquired data covered, overall, 1 day of tests along about 300 km of the Italian 3 kV DC railway network. [ABSTRACT FROM AUTHOR]

This study investigates the impact of different passenger rolling stock structures and train configurations on vibrations and noise generated during operation. Vibroacoustic measurements were performed during acceleration, constant speed, and braking phases to analyze the effects using statistical analysis according to the relevant standards, revealing a statistically significant relationship between the equivalent noise level and vibration dose. In the context of the expanding Warsaw metro network, which is adding new lines and modern rolling stock, trends in the development of metro rolling stock were analyzed using five different types of metro vehicles, from the oldest to the newest designs. Vehicle performance was ranked in the context of ride comfort using standards and combined vibration and noise measures. The research results allowed for a collective comparative assessment of the construction of individual types of passenger rolling stock in terms of vibroacoustic phenomena, thanks to which it is possible to assess the impact of modern solutions and the justification for investing in modern rolling stock. Newer trains generally record significantly lower vibration and noise levels. The difference between the oldest and the most modern vehicle types is 57% for the vibration acceleration level (0.08 ms−2 RMS) and 66% for the noise level (2.2 dB LAeq). [ABSTRACT FROM AUTHOR]

This paper considers the optimization of parameters for a railroad transport system. The maximum level of technological reliability and the average time spent by trains on the route are used as optimization criteria. The purpose of the study is to establish the optimal parameters for the operational process of railroad transport systems according to the criterion of the maximum level of technological reliability and the minimum time of trains on the route. Methods of technological reliability research have been proposed. Taking into account that the entire technological process is a sequential set of technological elements, a simulation model of the technological process of the transit transport-technological line along a route direction has been built. A population of agents that simulates the operation of railroad sections of the rotation of train locomotives and is a key subsystem of the simulation model has been developed and configured. The simulation model makes it possible to optimize the parameters of multi-section railroad lines. This approach is provided owing to the agent approach. As a result of the experiments, the optimal parameters of the functioning of railroad lines were established when organizing the passage of transit trains. The coefficient of utilization of the locomotive fleet fluctuates within the optimal range (0.55–0.65), which indicates the sufficiency of traction resources in the railroad system. The optimal parameters of the railroad transport system were established experimentally using the example of a train flow of 85 pairs of trains on a two-track route with five sections. The problem of "abandoned trains" has a solution but, to this end, it is necessary to increase the fleet of train locomotives by 150–200 % relative to existing standards. At the same time, even with an unlimited fleet of train locomotives, there is a fairly high probability (up to 30–50 %) of technological failures. [ABSTRACT FROM AUTHOR]

The rail rolling stock undercarriage condition monitoring is proposed by using an automated measuring system, located on the railway track and measuring the specified parameters of the wheels directly, while the train is moving. Regular undercarriage condition monitoring reduces the costs of preventive maintenance of rolling stock without compromising the traffic safety. An algorithm has been developed for the operation of a special software package for visualizing and assessing monitoring data on the condition of the undercarriage of rail rolling stock. The software package consists of separate software modules that can be used independently of each other. It is possible to make short- or long-term predictions of the behavior of any of the monitored parameters using an proposed automated measuring system. [ABSTRACT FROM AUTHOR]

This work describes the features and methods of measuring the forces of interaction between the wheel pairs and rails by measuring wheel deformations at control points. The work also contains recommendations for direct measurements of the forces of interaction between the wheels and rails to determine the actual margin of stability of wheel pairs from derailment. The result of the work is general requirements for the system of direct measurement of the strength of interaction of the high-speed rolling stock wheel pairs with rails and scientifically based recommendations for direct measurement of the interaction forces of wheels and rails. The problems of interaction between the wheel pairs and rails do not significantly depend on the track width and are general in nature for different countries of the world. [ABSTRACT FROM AUTHOR]

Energy saving has become a key concern of metro systems to reduce operating costs and meet the requirements of sustainable development. Energy-efficient timetabling, an effective way to reduce traction energy consumption, has gotten much attention in recent decades. However, limited research about energy-efficient timetabling simultaneously considered realistic speed profiles and the influence of train loads, which change greatly in different sections and significantly affect energy consumption. Therefore, this paper proposes an energy-efficient timetabling approach to improve regenerative energy utilization based on varying train loads and realistic speed profiles for bidirectional metro lines. First, based on the operational and safety constraints, this paper constructs an integer energy-efficient timetabling model where dwell times and nonuniform headways are taken as decision variables. Besides, the turnaround process is also considered to ensure rolling stock circulation efficiency. Sectional passenger volumes are employed to determine the varying train loads. Energy consumption is calculated based on realistic speed profiles. Owing to the complexity of the model, an improved adaptive large neighborhood search (ALNS) algorithm is designed to solve this model according to its characteristics. Finally, numerical examples are conducted based on the practical data from Shanghai Metro Line 17. The results indicate that the proposed approach effectively solves the energy-efficient timetabling problem with varying train loads and realistic speed profiles for bi-directional metro lines. The approach is suitable for off peak hours and can reduce energy consumption effectively, and the reduction is up to 11.9% for the presented cases. The improved ALNS algorithm can find good solutions within reasonable times in different cases. Moreover, compared with the widely used genetic algorithm in the literature, the improved ALNS algorithm is more efficient in solving the proposed energy-efficient timetabling problem in different cases. [ABSTRACT FROM AUTHOR]

This paper addresses timetable disruptions in metro systems and their impact on passenger service quality. To mitigate these effects, the study introduces a time-space network-based traffic management approach with a two-layer network. The first layer focuses on timetable rescheduling, using an integer program for modeling and a Lagrangian relaxation-based heuristic for solution. The second layer addresses rolling stock duty rescheduling, employing a greedy heuristic for train set duties. The proposed approach is applied to a real-world problem presented in the INFORMS railway application competition (2022). Results demonstrate that, with topological vertex orders, the approach achieves schedule amendments within 3–6 minutes for various disruption scenarios. This rapid response highlights the method's efficacy and advantage in real-time applications, showcasing its potential for practical implementation in metro systems. [ABSTRACT FROM AUTHOR]

Disturbance occurs inevitably on a metro line, resulting in train delays and low service quality. To improve the efficiency of disturbance management, this article investigates the integrated rescheduling problem of train timetable and rolling stock circulation. To balance service quality and operational cost, the considered problem is formulated as a multi-objective optimization model by capturing train operation processes as running arcs, dwell arcs and coming-out/back arcs based on the classical space–time network. For the purpose of improving computational efficiency, a Q-learning-based solution approach is proposed to derive a hierarchical policy for integrated rescheduling. The decisions on train timetable follow a lower-level policy that can be learned in the pre-training process, and the decisions on rolling stock circulation follow a higher-level policy that can be generated in the real-time planning process. Finally, two sets of numerical examples are carried out to evaluate the proposed method. [ABSTRACT FROM AUTHOR]

Driven by the concept of mass customization, manufacturing enterprises are now required to transform their traditional workshops into smart workshops. The integration of cyber-physical systems (CPS), which serves as the core of Industry 4.0, is crucial in achieving smart manufacturing. By implementing CPS, the conventional workshop can transition into a new paradigm characterized by intelligence and flexibility. However, the implementation of CPS in workshops is a complex undertaking that is still in its early stages. Therefore, this research paper aims to provide a comprehensive perspective on CPS-based workshops, with the intention of facilitating their implementation in the industry. Initially, the paper identifies seven key features of CPS-based workshops, namely self-sensing, self-awareness, self-assessment, self-optimization, self-adjustment, self-configuration, and self-control. Subsequently, the paper proposes the architectural framework of CPS-based workshops from a technical standpoint. Furthermore, a conceptual model of CPS-based workshops is developed, which highlights the three fundamental elements and closed-loop mechanism of such workshops. Finally, a case study of a Rolling stock manufacturing company in Indonesia is presented to demonstrate the feasibility of implementing CPS-based workshops in the industry. [ABSTRACT FROM AUTHOR]

Purpose. Highlighting the results of the analysis of the stress-deformed state of the wagon body of the 918 model under non-typical loads with bulk cargo. Such an analysis was carried out with the aim of investigating the possibility of transportation of various types of bulk cargo (for example, various types of raw materials, agricultural products, construction materials, etc.) in the existing design of the section of the refrigerated wagon. Methodology. In order to ensure uninterrupted railway transportation in today’s difficult conditions, it is proposed to use scientific and applied approaches to develop the possibility of using existing models of wagons for types of transportation that are not typical for them. Namely, to consider the possibility of using refrigerated wagons for the transportation of bulk cargo. A systematic approach is used to conduct such research. This included: determination of the study of the specifics of the impact of bulk cargo on rolling stock structures; analysis of design and technological documentation to create a spatial 3D model of the wagon under investigation; creation of a calculation model using a modern software complex; checking the adequacy of the developed model and the accuracy of the data obtained with its help; application of non-typical design loads; obtaining and analyzing pictures of stress-strain states by the finite element method. Findings. A 3D model of the body module of the model 918 wagon was developed. The results of the analysis of the equivalent stress plot according to the first mode proved that the greatest stresses are 800 MPa, that is, they significantly exceed the permissible ones. According to the third mode, the highest stresses are 320 MPa and also exceed the permissible ones. The results of the analysis of the plot of equivalent stresses, which occur during expansion, proved that the loads are excessive. The cladding, supported only by racks, cannot hold the load from the bulk cargo. Originality. A strength analysis of the existing design of a refrigerated wagon section was conducted under non-typical bulk cargo loads. Practical value. The obtained results of the analysis of the stressed-deformed state of the body of the model 918 wagon when loaded with bulk cargo made it possible to assess the potential possibilities of such transportation. It is expedient to use such results when carrying out research and development works on the improvement (modernization) of the existing sections of refrigerated wagons to ensure the possibility of transporting bulk cargo in them. This, in turn, will increase the efficiency of the domestic fleet of freight wagons. [ABSTRACT FROM AUTHOR]

The paper deals with the problem of obtaining a given dynamic behavior of simply supported bridge beams from the impact of rolling stock. Resonant vibrations of beams become a reality at high speeds if the train is formed of identical cars, which is typical for passenger trains. The phenomenon of suppression of beam vibrations by a train, known from publications, is possible only with an exact ratio of the length of the car and the beam. This significantly reduces the possibilities of choosing the necessary spans of beams. Consideration of issues of interaction in the "bridge–track—train" system for security purposes requires the involvement of a rather complex mathematical apparatus and appropriate software. The paper proposes a new method for determining the specified dynamic behavior of bridge beams, suitable for any spans and available to engineers at the stage of pre-design assignment of dynamic parameters of beams. The requirements that are necessary and sufficient conditions for preventing the resonance of bridge beams on the HSR are determined. At the same time, it does not require the involvement of software based on a complex mathematical technique. [ABSTRACT FROM AUTHOR]

The advancement of virtual coupling technology in urban rail transit has facilitated the online coupling and decoupling of trains, enabling a range of flexible transportation configurations, including various route types and adjustable formations. This study targets the fluctuating passenger demands on urban rail lines, aiming to minimize both passenger travel and operational costs. The model integrates constraints associated with virtual coupling, train operations, rolling stock circulation, and the interaction between virtually coupled trains and passenger arrivals. New decision variables are introduced to depict the train formation state under virtual coupling scenarios. An integrated optimization model for train diagrams and rolling stock circulation under virtual coupling conditions is developed, employing a genetic-simulated annealing algorithm informed by train operation simulations. A case study on an urban rail line during the morning peak examines the optimization of train diagrams for full-length and short-turn routes. Findings confirm that virtual coupling technology effectively adapts to lines with uneven passenger flow distribution, significantly enhancing the match between supply and demand, equalizing spatial and temporal traffic variations, and harmonizing the quality of passenger services with operational efficiency. [ABSTRACT FROM AUTHOR]

High-speed trains have to undergo special maintenance services. The maintenance service is highly specialized and can only run on specific platforms. Most of the optimization models proposed in the literature do not consider this problem integrated with the rolling-stock planning, although the two problems affect each other, and their separation leads to suboptimal solutions of the overall problem. This article presents an integrated approach based on a mixed integer mathematical formulation and computational results on a testbed of instances, derived from a real-world case study. This approach is compared with a two-stage one, commonly used in practice and in the literature. The results show that the rolling-stock planning problem can produce input parameters for the scheduling problem for which no feasible schedules exist. When a scheduling solution exists, the final percentage gap of the two-stage solution is much higher than the one provided by the integrated model. [ABSTRACT FROM AUTHOR]

Nowadays, the dynamic behavior of rolling stocks is an essential problem. In dynamic simulation, the correct wheel-rail contact modeling is an important task. In this paper, the stiffness of the wheel-rail contact zone is found by a new, direct, and simplified formulation. This subject is developed by applying more details, such as surface roughness based on the surface topography and hardening effects of a real contact problem. These characteristics have not been considered altogether in other similar works. In this work, the contact stiffness and frequency results are obtained for different material properties and verified with analytical and experimental research. It is shown that the presented new direct method with an acceptable accuracy is easier to use than the complicated existing methods. This paper discusses the effects of contact parameter variations on contact stiffness and frequency. For example, it is shown that the contact stiffness decreases by increasing the surface roughness and increases by increasing the strain-hardening factor. [ABSTRACT FROM AUTHOR]

Rolling stock manufacturers are finding innovative structural solutions to improve the quality and reliability of railway vehicles components. Structural optimization processes represent an effective strategy for reducing manufacturing costs, resulting in geometries easier to design and produce. In this framework, the present paper proposes a new methodology to design a railway metro bogie frame, combining structural–topological optimization methods and sensitivity analysis. In addition, manufacturing constraints were included to make the component design suitable for production through sand-casting. A robust sensitivity analysis has highlighted the most critical load conditions acting on the bogie frame. Its effectiveness was verified by carrying out two different structural optimizations based on different loadings. Two equivalent designs were obtained. Computational times were positively reduced by about 57%. The maximum value of stress was reduced about 23%. This new methodology has shown encouraging results to streamline the design process of this complex mechanical system, allowing researchers to also include manufacturing requirements. [ABSTRACT FROM AUTHOR]

ATC signal equipment is an important equipment for controlling rolling stock (subways). The on-board system is closely connected with the control circuit system of the vehicle, and there are many electrical interfaces and information interfaces between them. As the on-board ATC signal equipment and the vehicle belong to two systems, the joint debugging between the systems is aff ected by many factors such as time, site and so on. At present, there is no equipment available that can independently detect the internal digital signal functions of the boards and cards onboard the vehicle, and there is a lack of special tools to verify the functions of the boards and cards after medium and large-scale overhaul. There are safety risks during the dynamic debugging on the test line after static overhaul. This paper mainly describes a debugging device that replaces professional vehicle equipment. The device is connected with the female head of int connector. Under the static condition of the train, OMAP software is used to force and drive the internal digital signal of the board or card, so as to test whether the internal contact of the board or card works normally. The positions of faulty components can be accurately identified before dynamic train testing. This device improves the efficiency of dynamic train debugging and further improves the maintenance quality and standard. [ABSTRACT FROM AUTHOR]