Rolling Stock Research Articles

Criteria for evaluating offers in tender procedures for the purchase of new rolling stock

The article presents the currently used criteria for evaluating offers in tender procedures for the purchase of new rolling stock. A literature review and the results of the analysis of tender procedures in three segments of rolling stock are presented: passenger cars, traction units and locomotives. The summary shows that the most important evaluation criterion remains the price criterion, which is in line with legal and formal requirements.

Auxiliary rail vehicles – characteristics of the Polish rolling stock for special purpose works based on European Vehicle Number (EVN)

The obligatory National Vehicle Register (NVR) requires that each rail vehicle operating on railway lines be assigned a 12-digit European Vehicle Number (EVN). This enables, among others, efficient data management on rail vehicles. The article presents the coding method of EVN for auxiliary rail vehicles intended for special purpose works. The number of auxiliary rolling stock, average age and technical parameters were also analyzed, taking into account the vehicle subgroups. The analyses show, among other things, that in Poland in 2021, 3737 auxiliary rail vehicles were assigned EVN, of which 1285 vehicles had their own propulsion system. In general, for this type of vehicles, the average age was 38.1 years.

Examining failures in rubber-cord couplings within ER2 series electric trains

The article provides statistics on failures of rubber-cord couplings of electric trains of the ER2 and ER2T series and of the diesel trains over the past 7 years. According to statistics, over the past 7 years, 107 rubber-cord couplings have failed. Of these, the largest number of cases of failure of rubber-cord couplings occurred on rolling stock of the ER2 series. Examining failed rubber-cord couplings, it was revealed that the cause of its failure was a rupture of the side surface. Replacing a rubber-cord coupling is a labour-intensive and costly process. Accordingly, the question arises: what causes the problem and what measures should be proposed to reduce the failures. For these purposes, the work presents a number of experiments in order to identify possible causes of failure of the rubber-cord coupling. The article presents studies of the heating temperature of rubber-cord couplings in operation on motor cars, as well as a number of studies of failed rubber-cord couplings removed from motor cars. During the research, such parameters as the date of the last repair and the date of failure of the rubber-cord coupling were taken into account. The number of days the motor car was in general operation was taken into account until the failure of the rubber-cord coupling, as well as the mileage of the motor car after the repair. Measurements were carried out of the geometric parameters of the rubber-cord coupling: outer and inner diameter, thickness of the side of the rubber-cord coupling. The torque of the rubber-cord coupling acting at speeds from 5 to 40 km/h, the forces acting in operation on the rubber-cord coupling were calculated, and torsional and shear stresses were also studied and determined. Research was carried out to determine the hardness of the rubber-cord coupling in the temperature range from –20 °C to 0 °C and from 0 °C to +22 °C, as well as from +22 °C to +60 °C. These parameters were taken since a rubber-cord coupling operates under the mentioned conditions. In conclusion, possible reasons for the failure of rubber-cord couplings are given, and recommendations for reduction of their frequency are proposed.

Influence of the geometric parameters of the connecting pipeline on the stiffness and damping of the pneumatic spring suspension at high-speed rolling stock

The study presents investigation is the pneumatic spring suspension system of diesel train DPKr-3. The research aims to estimate the influence of track irregularities on the pneumatic spring dynamic stiffness and its damping coefficient at 170–250 km/h speeds. The pneumatic spring suspension system characteristics were studied using an improved mathematical model of the system ‘rolling stock-track’. The pneumatic spring ‘force-strain’ relations are obtained at different values of the connecting pipeline diameter and length at high speeds. It was determined that increasing a connecting pipeline diameter from 20 to 40 mm and a speed change from 170 to 250 km/h causes decreasing a spring dynamic stiffness. It is shown that at a speed range from 170 to 250 km/h and a connecting pipeline diameter from 20 to 40 mm, a change in a pipeline length from 3 to 6 m does not lead to significant changes in stiffness. It was found that in the range of speeds from 170 to 250 km/h, the damping coefficient has maximum values with a diameter of the connecting pipeline from 25 to 30 mm.

Machine Vision AI in Railroad Safety: Advanced Inspection Techniques

This article explores the transformative impact of machine vision AI in railroad safety, focusing on advanced inspection techniques. It examines the integration of technologies such as line scan cameras, LiDAR, and IoT sensors in enabling comprehensive 360-degree inspections of railway infrastructure and rolling stock. The article discusses key innovations in continuous monitoring, data processing, and AI-driven analysis, highlighting their potential to significantly enhance defect detection accuracy, reduce maintenance costs, and prevent accidents. Real-world applications in structural integrity assessment and overhead line inspection are presented, along with an analysis of current challenges and future developments in the field. The article underscores the paradigm shift from reactive to proactive maintenance strategies, promising a safer and more efficient future for rail transport.

Effects of Movement Direction through a Switch on Accelerations and Natural Frequencies of a Pneumatic Suspension of High-Speed Rolling Stock

Effects of Movement Direction through a Switch on Accelerations and Natural Frequencies of a Pneumatic Suspension of High-Speed Rolling Stock

Discrete control model Q-learning for an energy storage system with a hydrogen unit of an autonomous hybrid power plant of a railway substation

The paper considers the prospects for creating autonomous hybrid power plants using renewable energy sources and hydrogen as energy storage systems, as well as storage batteries, for the railway power supply system. A comparative analysis of various energy storage systems is carried out. A simulation model has been created that takes into account the characteristics of electric rolling stock trains, a model of the contact network of the inter-station zone of the railway stage, and a model of the energy storage system. Managing the flow of electricity in an autonomous hybrid power plant requires considering forecasts of electricity consumption and generation and the level of charge of the energy storage device. To solve the problem of synthesizing a control algorithm, the use of matrix Q-learning is proposed. The novelty of the study lies in the proposed approach of applying Q-learning to the problem under consideration based on discretization of input and output parameters of the model and verification of the approach on a simulation model built for a real railway section between the Yaya and Izhmorskaya stations (Kemerovo region of the Russian Federation). It is shown that the use of the proposed system makes it possible to equalize the voltage in the network between traction substations and provide a significant increase in the capacity of the railway section, and the proposed method of matrix Q-learning makes it possible to synthesize an effective algorithm for controlling the energy storage system as part of an autonomous hybrid power plant.

Saving energy resources during operation of rolling stock of underground electrified transport

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.

Oновлення парку рухомого складу українських залізниць з орієнтацією на інтеграцію в європейські транспортні мережі

The strategic aim of further development of the Ukrainian railways is rolling stock and infrastructure renewal to meet the demands of the Ukrainian economy, including a rapid integration into the European transport service. The paper presents the results of recent studies conducted at the Department of Statistical Dynamics and Multidimensional Mechanical System Dynamics, the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, with the aim to solve important problems in the development of the Ukrainian railway transport. The studies were aimed at developing scientifically substantiated decisions on Ukrainian rolling stock renewal oriented at integration into the European railway networks. To do this, a cycle of theoretical and experimental studies was conducted at the department. Consideration was given to the problem of wheel–rail contact pair improvement by identifying a wheel profile that would offer an acceptable car ride performance and acceptable conditions of car–rail interaction both on the Ukrainian and the European railways and reduce vehicle and rail wear. The car ride performance of an articulated passenger train was simulated mathematically for its motion at different speeds along a track of arbitrary alignment and profile, and the effect of different car and track parameters on the ride performance was estimated. Energy-absorbing devices were developed to increase the passive safety of a speedy locomotive-hauled passenger train and a multiple-unit train in emergency collisions with obstacles according to the Ukrainian Standard DSTU EN 15227. Service loads on the load-bearing components of swap-body freight cars were estimated, and recommendations were developed on fasteners that would provide safe transportation of various freights in swap-body cars. Based on the results of the studies, a number of design solutions were proposed for Ukrainian railway vehicle components. Their implementation will offer a sizeable economic benefit, increase the train speed and safety, improve the vehicle–track interaction, and facilitate the formation of an up-to-date home railway complex and its integration into the European railway networks.

Adequacy of measures to threats as one of the fundamental ­principles of safety riskology

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.

INVESTIGATION OF VERTICAL AND HORIZONTAL DEFORMATIONS OF THE PNEUMATIC SPRING OF A HIGH-SPEED MOVING VEHICLE IN THE LIMITS OF THE ARROW OF THE ARROW GEAR

The object of the research is the pneumatic spring of the second stage of the spring suspension of the high-speed rolling stock of the railway. The vertical and horizontal deformations of the pneumatic spring within the scope of the arrow translation are studied. For constructive reasons, two sections of the turnout were chosen, namely the section of the tip of the spikes and the section of the root of the spikes. In order to determine the deformations of the pneumatic spring, a methodology for its full-scale testing has been developed, which includes the use of a test rig that has a rigid metal frame on which the pneumatic spring and measuring equipment are installed. High-frequency potentiometric linear displacement sensors were used to measure vertical and horizontal deformations. In accordance with the developed complex program of field tests, records of vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock were obtained during the movement of the turn signal in the forward and opposite directions. It was found that the vertical deformations of the pneumatic spring within the range of movement by the arrow transfer in the furrow and anti-furrow directions are greater than the horizontal ones. In addition, in the opposite direction of movement of the test rig, the vertical deformations of the pneumatic spring are larger compared to the opposite direction of movement. It was established that the maximum values of the vertical deformations of the pneumatic spring are within the range of 3.14–5.05 mm in the wool direction and 4.88–5.95 mm in the anti-wool direction. The maximum values of horizontal deformations are within 1.62–2.94 mm and 1.30–2.53 mm, respectively. It was established that the average value of the vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock within the range of the arrow of the turnout is: for forward motion – 3.85 mm and 2.02 mm, for forward motion – 5,48 mm and 1.82 mm, respectively. The obtained results will make it possible to proceed to the determination of the dynamic characteristics of the pneumatic spring, and at the stage of designing high-speed rolling stock to study its dynamic indicators and traffic safety indicators under different operating conditions.

Methods for separating the noise produced by the wheels and track during a train pass-by

AbstractRolling noise is produced by vibration of the wheels and track, induced by their combined surface roughness. It is important to know the relative contributions of the different sources, as this affects noise control strategies as well as acceptance testing of new rolling stock. Three different techniques are described that aim to use pass-by measurements to separate the wheel and track components of rolling noise. One is based on the TWINS model, which is tuned to measured track vibration. The second is based on the advanced transfer path analysis method, which provides an entirely experimental assessment. The third is based on the pass-by analysis method in combination with static vibroacoustic transfer functions which are obtained using a reciprocity method. The development of these methods is described and comparisons between them are presented using the results from three experimental measurement campaigns. These covered a metro train, a regional train and a high-speed train at a range of speeds. The various methods agree reasonably well in terms of overall trends, with moderate agreement in the mid-frequency region, and less consistent results at low and high frequency.

РАЗРАБОТКА ДВУХФАКТОРНОЙ МАТЕМАТИЧЕСКОЙ МОДЕЛИ ОЦЕНКИ КОЛИЧЕСТВА ДОРОЖНО-ТРАНСПОРТНЫХ ПРОИСШЕСТВИЙ С УЧАСТИЕМ ПАССАЖИРСКОГО ТРАНСПОРТА

The article considers the accident rate of passenger transport, determines perspective ways of development of this type of transport and the main target indicators in accordance with the Transport Strategy. The analysis of the main factors affecting the development of passenger transport - passenger turnover and availability of rolling stock - is carried out and a two-factor model is developed, which allows estimating the change in the accident rate depending on the changes in the factors under study.

Increasing the efficiency of railway rolling stock operation with induction traction motors due to implementation of the operational system for diagnostic condition of rotor

Increasing the efficiency of railway rolling stock operation with induction traction motors due to implementation of the operational system for diagnostic condition of rotor

Flammability and Mechanical Testing of Sandwich Composite for Rolling Stock Structural Applications

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.

Surface engineering of silica to control creep failure resistance of natural rubber-based composites for potential application in the suspension of rolling stock

Immobilization of polymer chains by silica on one side could increase the viscoelastic energy loss and on the other could postpone chain relaxations and temporarily conceal creep deformation. It is not yet clear how the formation of an interphase layer contributes to the change of creep resistance. Bifunctional silane, “Bis(triethoxysilylpropyl) disulfide” is employed to induce various degrees of covalent bonds at the rubber-silica interface, and also brings multiple degrees of immobilization. Interestingly, it was found that by controlling interfacial phenomena, the creep rate can be altered in a wide range of 4.35–1.65 (%/decade). It was mechanistically explained how the maximum creep resistance is observed for the sample having a medium level of surface treatment. The formation of a filler network indicated an essential role in increasing the high-temperature creep failure of systems having no favorable polymer-filler interaction.

Application of Surface Ultrasonic Waves for Detection of Contact Fatigue Cracks in the Rail Surface

The integrity and durability of rails plays a key role in train safety. However, the interaction of the rail head surface with the wheels of the rolling stock leads to high damage to these areas. The surface of the rail head is subject to the greatest damage, in which fatigue cracks develop on the surface with subsequent development. Timely detection of fatigue cracks in the rolling surface is possible using the ultrasonic technique using surface waves. To do this, the work investigated the sensitivity of a surface ultrasonic wave to obstacles in the surface of rails in the form of extended grooves, notches of finite length and known depth, as well as real cracks. The studies were carried out using the pulse-echo method at frequencies of 1.25, 1.8, 2.5, 4 MHz. Research has shown that surface waves are sensitive to surface fatigue cracks. The amplitude of the reflected pulses depends on the wavelength and the depth of crack propagation. The influence of the distance to fatigue cracks and the orientation angle of the transducer relative to the rail axis on the sensitivity of the surface wave to these defects was also studied. The results obtained allow us to conclude that the use of surface ultrasonic waves makes it possible to detect fatigue cracks in the crack surface. Thus, the use of the pulse-echo technique and surface wave converters makes it possible to detect contact fatigue cracks in the rail head, which can be used to eliminate them in a timely manner. The determination of their depth by amplitude is influenced by many factors, which are difficult to take into account in real conditions.

A Novel Application of Computational Contact Tools on Nonlinear Finite Element Analysis to Predict Ground-Borne Vibrations Generated by Trains in Ballasted Tracks

Predictive numerical models in the study of ground-borne vibrations generated by railway systems have traditionally relied on the subsystem partition approach (segmented). In such a method, loads are individually applied, and the cumulative effect of the rolling stock is obtained through superposition. While this method serves to mitigate computational costs, it may not fully capture the complex interactions involved in ground-borne vibrations—especially in the frequency domain. Recent advancements in computation and software have enabled the development of more sophisticated vibrational contamination prediction models that encompass the entire dynamics of the system, from the rolling stock to the terrain, allowing continuous simulations with a defined time step. Furthermore, the incorporation of computational contact mechanics tools between various elements not only ensures accuracy in the time domain but also extends the analysis into the frequency domain. In this novel approach, the segmented models are shifted to continuous simulations where the nonlinear problem of a rigid–flexible multibody system is fully considered. The model can predict the impact of a high-speed rail (HSR) vehicle passing, capturing the key intricacies of ground-borne vibrations and their impact on the surrounding environment due to a deeper comprehension of the occurrences in the frequency domain.

Damage Analysis of Rolling Stock Automatic Coupler under Cyclic Loads

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.

Railway noise monitoring - a tool to analyse in detail the evolution of noise over time during a rolling stock renewal period

As part of the commissioning of a rail freight project, a noise monitoring system was set up to track the increase in rail freight traffic and to monitor noise over time. Noise monitoring is done by continuous measurement stations, an analysis of the classic noise exposure indexes LAeq,6-22h and LAeq,22-6h is realized, completed by an analysis of several event acoustic indexes, with a distinction between the different traffic types (Freight, regional trains). In addition, the European Regulation EU 2019/774 on the application of the technical specification for interoperability relating to the subsystem 'rolling stock - noise' to the existing freight wagons, obliges the circulation of less noisy freight trains on certain itineraries called "Quieter routes" from 8/12/2024. The projected benefit will not be limited to the nearby residents of these routes but will, by indirect consequence, enable a gradual acoustic gain on all the French rail freight routes, due to the retrofit or renewal of the existing rolling stock. The goal of the noise monitoring system is also to quantify the acoustic gains from the indirect effects of this new regulation.