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Abstract Braking system performance is relevant for both railway safety and network optimization. Most trains employ air brake systems; air brake systems of freight trains mostly cannot achieve a synchronous application of brake forces, which is usually customary for passenger trains. The paper generalizes a previous air brake pneumatic model to passenger trains and describes the needed modifications. Among them, the way the pressure reduces in the brake pipe is generalized. Moreover, this paper reports an analytical bi-dimensional function for calculating the nozzle diameter equivalent to the electro-pneumatic (EP) or the electronically controlled pneumatic (ECP) brake valve as a function of the wagon length and the time to vent the brake pipe locally. The numerical results of the new model are compared against several experimental tests of high-speed passenger trains of Trenitalia, namely ETR500 and ETR1000. The model is suitable to be integrated into the UIC software TrainDy, aiming to extend its computational field to passenger trains and to simulate the safety of trains during a recovery.

Abstract The present paper shows the development of a strategy for the calculation of the air brake forces of European freight trains. The model is built to upgrade the existing Politecnico di Torino longitudinal train dynamics (LTD) code LTDPoliTo, which was originally unable to account for air brake forces. The proposed model uses an empirical exponential function to calculate the air brake forces during the simulation, while the maximum normal force on the brake friction elements is calculated according to the indication of the vehicle braked weight percentage. Hence, the model does not require to simulate in detail the fluid dynamics in the brake pipe nor to precisely know the main parameters of the braking system mounted on each vehicle. The model parameters are tuned to minimize the difference between the braking distance computed by the LTDPoliTo code and the value prescribed by the UIC 544-1 leaflet in emergency braking operations. Simulations are run for different configurations of freight train compositions including a variable number of Shimmns wagons trailed by an E402B locomotive at the head of the train, as suggested in a reference literature paper. The results of the proposed method are in good agreement with the target braking distances calculated according to the international rules.

Abstract The 20,000-ton combined train running has greatly promoted China’s heavy-haul railway transportation capability. The application of controllable train-tail devices could improve the braking wave of the train and braking synchronism, and alleviate longitudinal impulse. However, the characteristics of the controllable train-tail device such as exhaust area, exhaust duration and exhaust action time are not uniform in practice, and their effects on the longitudinal impulse of the train are not apparent, which is worth studying. In this work, according to the formation of the Datong–Qinhuangdao Railway, the train air brake and longitudinal dynamics simulation system (TABLDSS) is applied to establish a 20,000-ton combined train model with the controllable train-tail device, and the braking characteristics and the longitudinal impulse of the train are calculated synchronously with changing the air exhaust time, exhaust area, and action lag time under initial braking. The results show that the maximum coupler force of the combined train will decrease with the extension of the continuous exhaust time, while the total exhaust time of the controllable train-tail device remains unchanged; the maximum coupler force of the combined train reduces by 32.5% with the exhaust area increasing from 70% to 140%; when the lag time between the controllable train-tail device and the master locomotive is more than 1.5 s, the maximum coupler force of the train increases along with the time difference enlargement.

Abstract Assessment of railway wheel slide protection (WSP) systems involves the execution of complex experimental activities that are quite expensive and time-consuming, since they involve the physical reproduction of degraded adhesion conditions on a real railway line. WSP is devoted to regulating applied braking forces to avoid excessive wheel sliding in case of degraded adhesion conditions between wheel and rail. WSP must be also compliant to safety specifications related to assured braking performances and consumed air. Hardware in the loop (HIL) testing offers an affordable and sustainable way to accelerate these activities optimizing cost, duration and safety of experimental activities performed online. HIL test rigs are subjected to continuous updates, customization and natural ageing of their components. This work investigates the criteria that can be adopted to assure a continuous monitoring and validation of a real WSP test rig, the Italian test rig of Firenze Osmannoro.

Abstract The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive (e.g. in the case of depot operations) or highly inefficient (e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for low-speed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.

Abstract When fault occurs on cross-coupling autotransformer (AT) power supply traction network, the up-line and down-line feeder circuit breakers in the traction substation trip at the same time without selectivity, which leads to an extended power failure. Based on equivalent circuit and Kirchhoff’s current law, the feeder current characteristic in the substation, AT station and sectioning post when T–R fault, F–R fault, and T–F fault occur are analyzed and their expressions are obtained. When the traction power supply system is equipped with wide-area protection measurement and control system, the feeder protection device in each station collects the feeder currents in other two stations through the wide-area protection channel and a wide-area current differential protection scheme based on the feeder current characteristic is proposed. When a short-circuit fault occurs in the power supply arm, all the feeder protection devices in each station receive the feeder currents with time stamp in other two stations. After data synchronous processing and logic judgment, the fault line of the power supply arm can be identified and isolated quickly. The simulation result based on MATLAB/Simulink shows that the power supply arm protection scheme based on wide-area current differential has good fault discrimination ability under different fault positions, transition resistances, and fault types. The verification of measured data shows that the novel protection scheme will not be affected by the special working conditions of the electrical multiple unit (EMU), and reliability, selectivity, and rapidity of relay protection are all improved.

Abstract Inadequate management of large in-train forces transferred through coupler systems of a railway train leads to running and structural failures of vehicles. Understanding these phenomena and their mitigation requires accurate estimation of relative motions and in-train forces between vehicle bodies. Previous numerical studies have ignored inertia of coupling elements and the impacts between couplers. Thus, existing models underestimate the additional dynamic variations in in-train forces. Detailed multi-body dynamic models of two AAR (Association of American Railroads) coupler systems used in passenger and freight trains are developed, incorporating coupler inertia and various slacks. Due to the modeling and simulation complexities involved in a full train model, with such details of coupler system, actual longitudinal train dynamics is not studied. A system comprising only two coupling units, inter-connecting two consecutive vehicles, is modeled. Considered system has been fixed at one end and an excitation force is applied at the other end, to mimic a relative force transmission through combined coupler system. Simulation results obtained from this representative system show that, noticeable influence in in-train forces are expected due to the combined effect of inertia of couplers and intermittent impacts between couplers in the slack regime. Maximum amplitude of longitudinal reaction force, transferred from draft gear housing to vehicle body, is expected to be significantly higher than that predicted using existing models of coupler system. It is also observed that the couplers and knuckles are subjected to significant longitudinal and lateral contact forces, due to the intermittent impacts between couplers. Thus, accurate estimation of draft gear reaction force and impact forces between couplers are essential to design vehicle and coupler components, respectively.

Abstract The unsupported sleeper can change the load characteristics of ballast particles and thus affect the dynamic stability of a ballasted bed. In this work, a laboratory test was constructed on a ballasted track containing unsupported sleepers. The ballasted track was excited by a wheelset, and the influence of unsupported sleepers on the dynamic stability of a ballasted bed was studied. The results show that the main frequency of the sleeper vibration appeared at 670 Hz, and the first-order rigid vibration mode at the frequency of 101 Hz had a significant effect on the condition without the unsupported sleeper. When the sleepers were continuously unsupported, the vibration damping effect of ballasted bed within the frequency range of 0–450 Hz was better than that at higher frequencies. Within the frequency range of 70–250 Hz, the vibration damping effect of the ballasted bed with unsupported sleepers was better than that without the unsupported sleeper. Owing to the excitation from the wheelset impact, the lateral resistance of the ballasted bed with unsupported sleepers whose hanging heights were 30, 60, and 90 mm increased by 37.43%, 12.25%, and 18.23%, respectively, while the lateral resistance of the ballasted bed without the unsupported sleeper remained basically unchanged. The unsupported sleeper could increase the difference in the quality of the ballasted bed between two adjacent sleepers. In addition, test results show that the hanging height of the unsupported sleeper had little effect on the lateral resistance of a ballasted bed without external excitation, but had an obvious effect on the rate of change of the lateral resistance of a ballasted bed and the acceleration amplitude of the sleeper vibration under the wheelset impact.

Abstract: The article presents the research results into the influence of the content of a chemical-based stabilizing admixture in the form of starch on the change in the consistency of the concrete mix. The assessment of the impact of the stabilizing admixture dosed in the amount of 0.2%, 0.4%, and 0.6% in relation to the mass of cement on the change in consistency was made based on the cone drop test according to PN-EN 12350-2:2019-07. From the prepared concrete mixes, samples were also made for testing concrete density according to PN-EN 12390-7:2019-08 and compressive strength according to PN-EN 12390- 3:2019-07. For the developed composition of the concrete mix, a standard (reference) mix was prepared, which was used to compare the test results from samples containing admixture in different amounts. Based on the tests carried out, it was found that the applied stabilizing admixture based on starch with a different percentage share concerning the mass of cement significantly reduces the consistency. The use of an admixture in the case of a concrete mix with too high consistency gives the possibility of changing its purpose without affecting the other parameters. Keywords: Concrete mix; Starch; Concrete consistency

Abstract: The level of traffic noise depends mainly on road traffic parameters such as: traffic volume, share of trucks in traffic and vehicles speed. Traffic conditions determined by such parameters as, for example, the average travel speed, average delays at the intersection and the number of vehicles stops are also important. Their particular importance is revealed especially in the case of bad traffic conditions and a significant reduction of traffic flow. The paper presents selected methods of measuring road traffic parameters, and in particular - traffic conditions on the example of research on their impact on the noise level in the vicinity of the street and intersections. The results of these tests are also presented, determining the impact of such parameters on traffic noise as: instantaneous speed, sectional speed, average delays at the intersection entry, the number of vehicle stops, volume to capacity of the entry ratio. Keywords: Traffic noise; Traffic conditions; Traffic parameters; Measurement methods

Abstract: The paper discusses the issue of risk in transport projects. The first part includes the analysis of definitions developed to describe the notion of risk. Based on the studies of the literature on the subject, the author discusses the ways the scholars dealing with this subject- matter perceive risk. The second part includes the discussion of risk sources and factors in transport projects, depending on individual project implementation stages. The third part consists in the author’s analysis of risk sources together with the presentation of basic risk factors assigned to such sources which affect the possibility of reaching the set objectives as part of a transport project being implemented. Keywords: Risk; Source of risks; Risk factor

Abstract: Railway lines have an impact on the surrounding environment, both during the construction or modernization phase and during operation. Animal mortality due to collisions is an increasingly well-known impact, but usually the barrier effect that occurs as a result of line fencing is a much more serious threat. Collisions also have other aspects: train delays and damage, and a threat to traffic safety. Most often they occur in the morning and afternoon hours, and in the annual cycle during the mating season of a given species and after the separation of young animals from their mothers. Since the train does not resemble a predator, wild animals do not instinctively fear it and learn to ignore the movement of the trains. Keywords: Railway lines; Environmental impact; Wildlife

Abstract Air brake systems are critical equipment for railway trains, which affects the running safety of the trains significantly. To study air braking characteristics of long freight trains, an approach for simulating air brake systems based on fluid dynamics theory was proposed. The structures and working mechanisms of locomotive and wagon air brakes are introduced, and mathematical models of the pipes, brake valves, reservoirs or chambers, cylinders, etc., are presented. Besides, the dynamic motions of parts in the main valve are considered. The simulation model of the whole air brake system is then formulated, and the solving method based on the finite-difference method is used. New efficient pipe boundary conditions without iterations are developed for brake pipes and branch pipes, which can achieve higher computational efficiency. The proposed approach for simulating the air brake system is validated by comparing with published measured data. Simulation results of different train formations indicate that models that consider the dynamic behavior of brake pipes are recommended for predicting the characteristics of long trains under service braking conditions.

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

Introduction. The article is devoted to the study of the waves propagation of lightning overvoltage impulse in the catenary system of electrified railways. The purpose of the work is to determine the zone of waves propagation of lightning overvoltage impulse along the catenary system, the degree of attenuation and the influence of the soil condition on the mode of their propagation.Materials and methods. The authors carried out tests on the waves propagation of lightning overvoltage impulse along the catenary system of the 1st (ring) track and the 15th (dead end) track of the Experimental Loop of the Railway Research Institute at the Shcherbinka station using a high-voltage impulse voltage generator.Results. During the tests, the influence of the soil condition on the mode of waves propagation of lightning overvoltage impulse was determined. The degree of attenuation of the lightning overvoltage impulse wave in the catenary system in the looped and dead end sections is determined, considering the influence of the reverse (reflected) overvoltage wave, as well as changes in the voltage level during the wave process occurring in the catenary system. The data obtained during the tests enable to determine the propagation speed of the lightning impulse wave.Discussion and conclusion. The obtained test results will be useful for improving the reliability of lightning protection devices of the catenary system against external overvoltages and can be used to improve insulating elements.

Introduction. One of the ways to increase the traffic-carrying capacity of railway lines is increasing the amount of cargo carried in cars, while taking into account the inevitable increase in the axial and linear load of the car. The decision to use cars with increased axial load should be based on an assessment of their technical and economic efficiency in comparison with the innovative and widely used open-box wagons with a load of 25 tonnes per axle. When assessing the economic efficiency of such cars, it is required to consider their impact on changes in the parameters of the organisation of the transportation process.Materials and methods. Based on the presented initial data on the estimated predicted freight flow, the numerical values of the parameters of the transportation process were determined when introducing 8- and 4-axle (27 t/axle) open-box wagons. When determining the increase in the traffic-carrying capacity, its change due to an increase in the net mass of the train and a change in the total number of trains is taken into account. The calculation was made accounting for the increase in traction in proportion to the increase in the gross mass of the 8- and 4-axle (27 t/axle) open-box wagon trains on the existing infrastructure.Results. The authors have developed methodological provisions to determine the numerical values: an increase in the traffic- carrying capacity, the required inventory fleet of cars and the available locomotive fleet in the context of the introduction of new 8- and 4-axle (27 t/axle) open-box wagons.Discussion and conclusion. The article is theoretical and is devoted to calculation mechanisms and methodological issues. The results of the study may be applied to the ranges of the Russian Railways network, in particular, to solve complex issues of increasing the traffic-carrying capacity of the Eastern range.

Introduction. Until now, the requirements for manual and automatic couplers for locomotive-hauled passenger carriages and electric trains have been completely identical, despite the significantly lower level of longitudinal forces during the movement of multi-unit rolling stock with distributed traction. The introduction of specialised designs of coupling devices for electric trains led to the development of strength requirements that enable the creation of new models with smaller dimensions and weight. Operating experience has shown that parts of couplings may be destroyed, leading to the uncoupling of trains. Fatigue damage may cause accidents. However, there were studies of the draft loads of electric trains couplers in operation, on the basis of which it was possible to develop regulatory requirements for specialised coupling devices.Materials and methods. The authors measured the forces acting in the couplings of electric trains of various categories and types during normal operation, as well as the frequencies of the occurrence of forces of various levels. The article includes histograms based on the results of processing the received data showing the distribution of longitudinal forces acting on the inter-car couplers and the parameter characterising the accumulation of fatigue damage per 100,000 km. Results. According to the results of processing of the experimental data, the calculation of the accumulation of fatigue damage to the couplers was carried out and the requirements for their expected service life were established. Test procedures have also been developed to evaluate strength and fatigue resistance under high-cycle and low-cycle loading conditions. The article provides ground for introducing a correction factor into the procedure for processing test results, which makes it possible to perform life tests on equipment with different values of the load cycle asymmetry factor.Discussion and conclusion. The authors have evaluated the draft loads in coupling devices during the operation of electric trains, on the basis of which technical requirements and test methods were developed and approved by JSC Russian Railways. Development and acceptance of all new models of coupling devices for electric trains will be carried out in accordance with these regulatory documents.

Introduction. In the conditions of an annual increase in load stress on the roads of the Eastern Polygon, an effective technical solution to the problem of an increased number of rolling stock derailments due to rail breakage is the creation of rails for cold climate conditions with increased hardness to increase wear resistance and contact endurance with simultaneously high values of impact strength. Such a set of properties can be achieved by using separate heating for quenching and cooling with a quenching medium with a high cooling capacity. Rails manufactured using this technology will belong to a new category. In this regard, the purpose of this work was to create a new category of rails for their use in particularly harsh operating conditions.Materials and methods. In this paper the effect of separate induction heating before differentiated quenching with compressed air of controlled humidity on the microstructure and mechanical properties (hardness, mechanical properties during tensile and impact tests, endurance limit, cyclic crack resistance) of rails of type R65 was investigated.The results of the study. A comparative analysis of the results obtained with similar indicators for rails of the DT350, DT350NN and DT370IK categories according to GOST R 51685-2013 was carried out. Studies of the chemical composition, mechanical properties, hardness on the rolling surface of the rail head and cross-section, as well as the microstructure of the rails of the experimental batch showed compliance with the requirements of GOST R 51685-2013 for rails of categories DT350, DT370IK, DT350NN.Discussion and conclusion. It is shown that as a result of the application of differentiated thermal hardening of the rail using compressed air of controlled humidity as a quenching medium, a new category of DTO350NN rails was obtained, characterized by a favorable combination of strength properties, plasticity characteristics and brittle fracture resistance indicators. Rails of the new category can be recommended for use in particularly severe operating conditions (in curved sections of the track of a small radius at low temperatures), including on the roads of the Eastern Polygon.

Introduction. The aim of the study is to develop a basic configuration of the on-board system for diagnosing the technical condition of the wheels tread surface of a wagon while the train is running and to model its operation.Materials and methods. The theoretical studies are based on the methods of Lagrange's analytical mechanics, the theory of oscillations and classical electrodynamics. The simulation was carried out for a flat design scheme using numerical methods. The results were processed using the developed algorithm implemented in the programming language of the Mathcad system.Results. This article studies the problem of the negative impact of local wear of the wheel tread surface on the state of the carriage chassis of the car and the rail track, as well as on the safety of train traffic. The authors propose a basic configuration of an on-board system for diagnosing wheel pairs of a wagon with an autonomous power supply with a power of up to 10 W, which simultaneously acts as a sensor. A mathematical model of diagnostic signals for local wheel wear has been constructed, and an algorithm for their detection has been developed based on the results. A criterion for estimating the geometric parameters of wear is formulated and its threshold values for slots of various depths are calculated. Alarms have been identified that suggest a reduction in the speed of the train.Discussion and conclusion. The solution of the stated problem is important both in the operation of existing cars and in the development of new, innovative cars with an axle load of 27–30 tf and speeds of up to 140 km/h. Timely detection of local wear of the tread surface of wagon wheels will increase the level of traffic safety and reduce the cost of repairing cars and rail tracks.

Introduction. Replacing the material of monometallic motor-axial bearings currently manufactured from bronze to aluminium alloy is advisable to improve traffic safety due to the higher reliability and efficiency of such bearings.Materials and methods. This article studies the materials of monometallic motor-axial bearings, bronze and the proposed complex aluminium-tin alloys. Mechanical properties are determined by standard methods: tensile strength, relative elongation (ductility), Brinell hardness, impact strength. Antifriction properties (abradability, score resistance, wear resistance of the antifriction alloy and the steel associated with it, the heating temperature of the steel surface and the coefficient of friction) were determined according to the methods of the Railway Research Institute approved by JSC Russian Railways on the SMTs-2 friction machine. Bronze and three grades of aluminium alloys were tested with M-14V2 diesel oil, and bronze, B16 babbitt and one grade of aluminium alloy were tested with axial oil.Results. This research shows the possibility of replacing bronze with complex-alloyed aluminium alloys both in terms of economic indicators and antifriction properties. A comparison of mechanical properties is carried out, in most of which aluminium alloys are found superior or not inferior to bronze. The exception is ductility, in terms of which bronze surpasses the proposed alloys.Discussion and conclusion. According to the complex of service characteristics obtained in laboratory studies, it seems expedient to replace bronze with complex aluminium antifriction alloy. The final decision on such a replacement could be made after bench and operational tests of motor-axial bearings on diesel locomotives.

Introduction. On-board fuel metering systems for diesel locomotives created by different manufacturers differ both in the composition of the sensors used and in the software for processing the registration data. This indicates that the pursuit of better efficiency for these systems is still ongoing and is an urgent problem.Materials and methods. The article discusses the problems of determining the fuel consumption according to the data of on-board fuel metering systems for diesel locomotives, associated with various methods for determining the moments of measuring the fuel amount in the tank. The possibility of estimating the influence of the number of position switches of the locomotive throttle on the indicators of absolute and specific fuel consumption has been studied.Results. In the absence of distance and speed sensors in the on-board system, it is proposed to determine the moments of measurement of the fuel amount based on the analysis of changes in the signals of the fuel level sensors over time. The authors present an example of the practical implementation of this solution. The results of on-board systems data processing are also presented, showing that the effect of the spread in the number of throttle position switches observed in ordinary operation of diesel shunter on fuel consumption is comparable to the error in determining this value according to the on-board systems data. The implementation of algorithms in specialised software designed to process data from onboard systems that allow identifying the indicated influence is relevant only for cases of extreme (by an order of magnitude) difference in the number of switching throttle positions in work shifts.Discussion and conclusion. The efficiency of the practical use of information from the on-board systems for metering fuel consumption of a diesel locomotive is largely determined by the quality of specialised software. When developing and improving software, it is recommended to use the approaches discussed in the article.

Abstract: The article analyzes the main directions of long-distance rail transport in Poland, confronting them with the main directions of population movements in individual road transport, which allowed for the formulation of a general conclusion as to the polycentric rather than monocentric system of the Polish land transport network, in which the main passenger flows are closed in two circles. The smaller circle is formed by Warsaw, Łódź, Poznań and Bydgoszcz with Toruń, while the larger one is defined by the main cities of northern, eastern, southern and western Poland. On the basis of this analysis, a general recommendation was formulated that when designing the spatial and geographical layout of new high-speed railway lines, the layout of passenger flows inside the country should also be taken into account. The new concepts of the geographic route of high-speed railway lines related to the railway component of the project to build the Central Communication Port (CPK) in Poland do not fully take into account this postulate because they have been completely subordinated to the function of transporting and transporting passengers to the planned central airport. In the further part of the article, after a critical analysis of the assumed spatial and geographical routes of new high-speed lines Warsaw - Łódź - Poznań / Wrocław, the CPK - Płock - Grudziądz - Gdańsk line and the designed sections of high-speed lines for the CPK - Rzeszów transport route, specific corrections of their spatial routes are proposed. Keywords: Railway development in Poland; Railway component of the CPK project; High Speed Railways

Abstract: The article explores the possibility of using railway vehicle simulators and train traffic management station simulators for training Warsaw metro employees. The great benefits of using simulators are pointed out. On the basis of experience, positive opinions of candidates and employees who already have qualifications in terms of the possibility of practicing many incidental situations rarely occurring in reality have been observed. The use of simulators allows for the repetition of the same exercises for all employees and the initial verification of the trainee's predisposition to perform given activities. Keywords: Training; Simulator; Metro

Abstract: This article describes the conditions for the functioning of railway transport in the area of the Warsaw agglomeration, the legal conditions for the functioning of metropolitan areas and attempts to define the areas of development and limitations for sustainable transport. Due to the professional experience of the authors, an additional issue discussed in this study will be the functioning of rail transport on the example of the Fast Urban Railway sp. z o.o. in Warsaw. Keywords: Agglomeration; Railway transport; Suburban train

Abstract: The aim of this article is to present the results of a survey, conducted among entrepreneurs and managers responsible for transport and logistics, relating to the role of environmental factors in shaping the transport market. Analysis of the results allows for an assessment of the current and future importance of environmental issues affecting the transport market. The text includes a brief introduction, a description of the research methodology and a presentation of the results and observed trends. It concludes with a summary, indicating the evolution of the elements determining transport contracting and the resulting growing development potential for rail transport. Keywords: Sustainable Transport; Green Supply Chains; Climate Policy; Freight Rail Development

Abstract A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit. With the application of two-stage three-phase continuous power supply structure, the electrical characteristics exhibit new features differing from the existing traction system. In this work, the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive. The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses. Based on the chain network model of the traction network, a simulation model is established to analyze the electrical characteristics such as traction current distribution, voltage losses, system equivalent impedance, voltage distribution, voltage unbalance and regenerative energy utilization. In a few words, quite a lot traction current of about 99% is undertaken by long-section cable network. The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure, and the voltage unbalance caused by impedance asymmetry of traction network is less than 1‰. In addition, the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Abstract: The load-bearing capacity of natural airport surfaces directly affects the safety of air operations. Natural airport surfaces at military airports are front seat belts, work belts and side seat belts. The load-bearing capacity of the natural airport pavements must be high enough to prevent damage to the aircraft from the runway, damage to the underground infrastructure of the airport, and to enable quick restoration of the airport's operational capacity by efficient removal of the aircraft from the natural surface by airport services. That is why it is so important to have a quick and effective method of strengthening natural surfaces. The article proposes to improve the load-bearing capacity of natural airport pavements by using geogrids (airport gratings) pressed into the existing pavement. Keywords: Carrying capacity; Natural airport pavement; Safety Conducting air operations

Abstract: The intensification of air operations in recent years has resulted in an increase in stresses and deformations in concrete pavements. In terms of mass, dynamic and temperature interactions, these are measurable phenomena that can be determined and predicted using appropriate methods and algorithms. Another type of impact that does not occur in an avalanche-like manner on pavements is their random destruction caused by the presence and operation of exploitation media. The article presents the impact of selected measures on the change of concrete parameters and its durability in the pavement structure. The effects of this impact are significant and clearly destructive for concrete pavements. In addition to the measurable decrease in the mechanical parameters of concrete, there is an interference of media with the concrete structure, which in the presence of extreme temperatures (positive and negative) is a challenge for concrete technologists, contractors and users of airport pavements. The nature of the impact of exploitation media is varied and in most cases there is a combined effect of them on pavements. It has been shown that the operational coatings currently applied to pavements are only partially effective for these media, and learning about the nature and manner of impact makes it possible to effectively limit these unfavorable, objectively occurring phenomena. Keywords: Concrete airport pavement; Operating media

Abstract: The parameter defined as the coefficient of friction is one of the basic parameters that are responsible for the characteristics of the surface on which vehicles (cars, aircraft) travel. The coefficient of friction is very important as it is responsible for the safety and relia- bility of the pavement. The paper below presents general issues concerning the friction force and its influence on the movement of aircraft on airport pavements. The requirements for the assessment of the friction coefficient were also discussed. Based on the results of tests carried out at four airports, an analysis of the decrease in the value of the friction coefficient was per- formed. Keywords: Friction; Runway; ASFT

Abstract: The publication presents the requirements for airport pavements for the assessment of the evenness of airport pavements, including the methodology of testing unevenness. On the basis of the selected aircraft type, the impact of unevenness on the dynamic interaction of the plane - pavement was determined, and the vertical displacements occurring at the edges of concrete slabs were taken for analysis. The paper presents the influence of operational procedures in the form of pavement grooving and local surface repairs on the results of unevenness measurements and improvement of the technical condition of the pavement, as well as on the safety of air operations. Keywords: Pavement unevenness; Evaluation criteria; Dynamic action plane - surface; Grooving pavement; Maintenance treatments; The functional element of the airport

Abstract In this work, a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train–track–substructure (TTS) system. It is called implicit-explicit integration and multi-time-step solution method (abbreviated as mI-nE-MTS method). The TTS system is divided into train–track subsystem and substructure subsystem. Considering that the root cause of low efficiency of obtaining TTS solution lies in solving the algebraic equation of the substructures, the high-efficient Zhai method, an explicit integration scheme, can be introduced to avoid matrix inversion process. The train–track system is solved by implicitly Park method. Moreover, it is known that the requirement of time step size differs for different sub-systems, integration methods and structural frequency response characteristics. A multi-time-step solution is proposed, in which time step size for the train–track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand, namely the time spent for m implicit integral steps is equal to n explicit integral steps, i.e., mI = nE as mentioned above. The numerical examples show the accuracy, efficiency, and engineering practicality of the proposed method.

Abstract Stress concentration occurs in the foundations of railway tracks where discontinuous components are located. The exacerbated stress under the expansion joints in slab tracks may trigger foundation failures such as mud pumping. Although the higher stress due to the discontinuities of track structures has been discussed in past studies, few focused on the stress response of roadbeds in slab tracks and quantitatively characterized the stress pattern. In this paper, we performed a dynamic finite element analysis of a track-formation system, incorporating expansion joints as primary longitudinal discontinuities. The configurations of CRTS III slab tracks and the contact conditions between concrete layers were considered. Numerical results show that longitudinal influencing length of induced stress on roadbed under wheel load relates to the contact conditions between concrete layers, increasing nonlinearly at a larger coefficient of friction. Given a measured coefficient of friction of 0.7, the calculated longitudinal influencing length (9.0 m) matches with field data. The longitudinal influencing length is not affected with the increasing velocity. As stress concentration arises with expansion joints, the worst-case scenario emerges when double-axle loads are exerted immediately above the expansion joints between concrete bases. A stress concentration factor C v on the roadbed is proposed; it increases with the increasing velocity, changing from 1.33 to 1.52 at velocities between 5 and 400 km/h. The stress distribution on roadbeds transforms from a trapezoid pattern at continuous sections to a triangle pattern at points with longitudinal discontinuities. An explicit expression is finally proposed for the stress pattern on roadbed under expansion joints. Although structural discontinuities induce stress raiser, the extent of concentration is mitigated with increasing depth at different velocity levels.

Abstract We investigate numerically the dynamical reactions of a moving wheelset model to real measured track irregularities. The background is to examine whether the dynamics are suitable as the input to the inverse problem: determine the true track geometry from measured wheelset dynamical reactions. It is known that the method works well for the vertical position of the rails but the computed lateral position is often flawed. We find that the lateral motion of the wheelset often may differ from the track geometry. The cases are investigated closely but the reasons remain unknown. While the wheelset dynamics reflect the larger (> 4–6 mm) aperiodic track disturbances and single large disturbances quite well, this does not seem to be the case for general smaller or periodic track irregularities or sections behind single large disturbances. The resulting dynamics of a wheelset to lateral track irregularities are in general not sufficiently accurate to be used as the basis for a description of the track irregularities.

Abstract The delay-causing text data contain valuable information such as the specific reasons for the delay, location and time of the disturbance, which can provide an efficient support for the prediction of train delays and improve the guidance of train control efficiency. Based on the train operation data and delay-causing data of the Wuhan–Guangzhou high-speed railway, the relevant algorithms in the natural language processing field are used to process the delay-causing text data. It also integrates the train operating-environment information and delay-causing text information so as to develop a cause-based train delay propagation prediction model. The Word2vec model is first used to vectorize the delay-causing text description after word segmentation. The mean model or the term frequency-inverse document frequency-weighted model is then used to generate the delay-causing sentence vector based on the original word vector. Afterward, the train operating-environment features and delay-causing sentence vector are input into the extreme gradient boosting (XGBoost) regression algorithm to develop a delay propagation prediction model. In this work, 4 text feature processing methods and 8 regression algorithms are considered. The results demonstrate that the XGBoost regression algorithm has the highest prediction accuracy using the test features processed by the continuous bag of words and the mean models. Compared with the prediction model that only considers the train-operating-environment features, the results show that the prediction accuracy of the model is significantly improved with multiple regression algorithms after integrating the delay-causing feature.

Abstract The load spectrum is a crucial factor for assessing the fatigue reliability of in-service rolling element bearings in transmission systems. For a bearing in a high-speed train gearbox, a measurement technique based on strain detection of bearing outer ring was used to instrument the bearing and determine the time histories of the distributed load in the bearing under different gear meshing conditions. Accordingly, the load spectrum of the total radial load carried by the bearing was compiled. The mean value and class interval of the obtained load spectrum were found to vary non-monotonously with the speed and torque of gear meshing, which was considered to be caused by the vibration of the shaft and the bearing cage. As the realistic service load input of bearing life assessment, the measured load spectrum under different gear meshing conditions can be used to predict gearbox bearing life realistically based on the damage-equivalent principle and actual operating conditions.

Introduction. This article investigates the influence of the aerodynamic parameters of the current collector on the contact force. For this purpose, the influence in the speed range up to 160 km/h on the quality of the current collection, in particular on the increased wear of the current collector contact strips, was determined.Materials and methods. A method for calculating aerodynamic forces was developed using mathematical modelling by the method of computational fluid dynamics. The current collector can be conditionally divided into three parts: the base, the current collector lifting mechanism and the current collector head. The main characteristic of this interaction is the force with which the head is pressed against the contact wire and the stability of this force in dynamically changing external conditions.Results. The simulation performed showed that at a speed of about 140 km/h, head vibrations occur that change the contact force. This made it possible to explain the increased wear of the inserts during testing and commissioning of electric trains of the ES2G and ET4A types, which use the same type of current collectors. The presence of the current collector holder near its head, which is a pipe located along the entire length of the head at a slight distance, fundamentally changes the flow pattern. Based on the performed mathematical modelling, changes were made to the design of the current collector head in order to improve its aerodynamic properties. Other current-collecting elements were used to ensure stable aerodynamic properties of the head in a given speed range.Discussion and conclusion. The introduced changes made it possible to solve the problem with increased wear of the contact strips at a speed of up to 160 km/h. The conducted studies and the introduction of changes in GOST 32204–2013 based on these studies will improve the reliability and durability of the current collection devices.

Introduction. The tasks of increasing energy saving in heating systems for passenger cars of diesel trains are currently relevant. As an alternative source of energy for these systems, the possibility of using the waste heat of the diesel locomotive engine is analysed.Materials and methods. The article provides an analysis of the engine waste heat sources, cooling water and exhaust gases. A schematic diagram of exhaust gas heat exchanger for its use in the heating system of passenger cars has been deve loped. As a possible heat-exchange surface of the waste heat exchanger, plate-ribbed, coiled and tube surfaces with longitudinal boundary layer turbulators are proposed. The required area of this surface for the maximum power of the heating system for a passenger train is determined.Results. The article shows the possibility of using engine exhaust heat in the heating system of a 15-car passenger train without involving third-party energy sources.Discussion and conclusion. The obtained results demonstrate a sufficient potential for increasing the efficiency of using the diesel engine fuel energy when utilising its waste heat for the heating system of passenger cars. The selection of a waste heat exchanger is justified based on a performance of 50 % of the peak load on the heating system at the middle position of the controller.

Introduction. The transport and logistics business has undergone significant changes while overcoming the challenges facing the transport industry. It requires new approaches to rational use, as well as the introduction of innovative technologies in the organisation of foreign trade transportation. This issue is especially relevant in the Far East region, where there is an imbalance of incoming freight flows and traffic capacity of the transport network, which leads to a decrease in the quality of transport services and the competitiveness of transport corridors running through Russia. The key elements of international transport corridors are transport hubs and border checkpoints; therefore, the purpose of the study is to assess the workload of a railway cargo terminal of the Pogranichny checkpoint within the Primorye-1 transport corridor. The object of study is the terminal and logistics complex of the Grodekovo border station.Materials and methods. In this study, methods of system analysis and information synthesis were used, as well as a programme for simulating the operation of technological zones of a border terminal and logistics centre.Results. The developed simulation programme made it possible to assess the workload of the warehouse terminal of the Grodekovo border station for processing foreign trade freight flow arriving by rail and road from Heilongjiang Province (PRC). The article presents the results of simulation modelling.Discussion and conclusion. Analysis of the results of simulation modelling showed the functioning of the cargo terminal of the Grodekovo border station with an increase in freight flow coming by road for reloading onto railway rolling stock, taking into account the duration of customs clearance, the limited capacity of the storage area and the cargo front, the number of handling equipment. Further research is aimed at creating a comprehensive programme that takes into account the traffic capacity of the entire system of ground checkpoints in the Far East region and the volume of the predicted freight flow.

Introduction. The formation of an overarching network of nodal freight multimodal transport and logistics centres in the Russian Federation and organisation of high-speed freight traffic on schedule on its basis requires the development of science-based proposals for the creation or modernisation of the corresponding regional transport and logistics infrastructure. One of the most important tasks in the implementation of this project in the context of limited investment resources is the correct justification of the number and choice of locations for the transport and logistics centres of the overarching network in the Russian Federation, as well as the locations of transport and logistics centres in the constituent entities of the Russian Federation.Materials and methods. This article provides an evaluation analysis of the classical methods for finding optimal centres on a plane and some construction of mathematical quantitative models for the optimal placement of transport and logistics facilities.Results. According to the evaluation analysis, the authors have drafted a scientifically based concept of a systematic approach to the issues of rational design and placement of elements of transport and logistics infrastructure, in particular, the overarching network of nodal freight multimodal transport and logistics centres, as part of a new highly efficient transport and logistics infrastructure of the Russian Federation and its international transport corridors.Discussion and conclusion. The obtained results of the study can be used for scientifically based decision-making in investment projects related to the development of transport and logistics infrastructure at both regional and federal levels: substantiation of locations and technological capacities of transport and logistics infrastructure facilities; determining the need for the development of objects of the regional transport and logistics infrastructure, while eliminating their bottlenecks; implementation of a phased set of measures to modernise the existing terminal and logistics complex.

Introduction. The purpose of the study is to develop measures determined by the strategic programmes for the development of Russian railway transport based on the analysis of power supply schemes for the traction network of the Far Eastern Railway, a branch of Russian Railways.Materials and methods. Evaluation of the performance of the traction power supply system was made based on the analysis of the actual performance of the Far Eastern Railway section, as well as the theories of electrical engineering and power supply of the 25 kV AC electrified railway system.Results. Based on the analysis of the joint operation of the external and traction power supply systems of the Far Eastern Railway, four traction substations with low technical and economic indicators were identified. Network sections that feed the substations are a bottleneck in the traction power supply system. It is proposed to increase the efficiency by switching the connection of the windings of transformers of traction substations to the systems of external and traction power supply according to the typical star – delta scheme. Such a connection will ensure an increase in the speed of trains, a reduction in train succession time and losses of electricity, an increase in the quality of electric energy in the external power supply system and electric networks of the Far Eastern Directorate for Energy Supply (a structural subdivision of Transenergo, a branch of Russian Railways).Discussion and conclusion. Normalisation of the connection of four traction substations according to the feeding scheme is ensured by changing the phasing in such a way that the power supply of the two legs of one winding of the power transformer is transferred to two windings. Alignment of the current modules in the windings of transformers of traction substations makes it possible to reduce the voltage drop in the most loaded phase and, accordingly, increase the voltage in the traction network, which ensures an increase in the speed of trains and a reduction in passing intervals. Switching the power supply of the arms from one winding of the transformer to two reduces the loss of electrical energy in power transformers and the external power supply system. Reducing the current unbalance in the windings of the power transformer improves the quality of electrical energy in the system of external and district power supply. An increase in the service life of the power transformer is ensured by a decrease in the intensity of thermal wear of the insulation of the most loaded winding.

Introduction. The issue of ensuring the operable state of the DC traction motor is relevant due to its large-scale use on diesel locomotives, including modern powerful motors, operating on lines with increased train masses. At present, a rather difficult situation has developed in the locomotive industry with the failure of diesel locomotive traction electric motors due to a decrease in the insulation resistance of the armature windings of the electric motors and their subsequent breakdowns: up to 28 % of the total number of failures of electric motors are due to breakdown of the hull insulation and interturn short circuit of the armature and 13 % of cases are due to reduction in the resistance of the insulating material.Materials and methods. The paper considers the main directions of scientific research on the causes of insulation integrity failure, which lead to unscheduled repairs of traction motors. The theoretical substantiation of the root causes of insulation destruction is based on the importance of taking into account the coefficients of thermal linear expansion of copper and its insulating materials. In order to study thermodynamic processes in the winding of a traction motor, a computational finite element model of a winding coil laid in the groove of the armature core has been developed. The winding model is represented separately by a conductor and insulation, between which contact conditions are specified. The conductor of the calculation model heats up to 120 °C from the current flow. Mathematical apparatus embedded in the MSC calculation program, Patran – Nastran, made it possible to evaluate the deformation of the conductor relative to the insulation as a result of a linear increment due to thermal expansion.Results. With the help of mathematical modelling and based on the results of finite element analysis, the confirmation of the theoretical justification is clearly shown. The difference in elongation during heating of the motor armature conductor and insulation, obtained by mathematical modelling, is 0.6 mm and is significant for the winding (consisting of a conductor and insulation), which is usually considered as a single whole body.Discussion and conclusion. The obtained result shows the need for more detailed studies to select the technology for the insulation of the DC traction motor. The use of insulating materials for the armature winding with coefficients of thermal linear expansion equal to the coefficient of thermal expansion of the copper conductors of the winding will improve the reliability of traction electric motors of diesel locomotives in operation.

Introduction. Every year, the amount of electric rolling stock with asynchronous traction motors is continuously increasing on the Russian railway network, since such traction drives have a number of advantages over drives with DC motors. One of the problems associated with the introduction of asynchronous motors and an increase in the mass of trains is the implementation of the maximum traction force by an electric locomotive at the threshold in terms of wheel – rail adhesion. Timely recognition of excessive slip of wheel pairs is the most important indicator of the efficiency of the traction drive in realising the maximum traction properties of the electric locomotive at all axles.Materials and methods. The article reflects the results of the study of slip of electric locomotive wheel pairs with asynchronous traction motors and axial control of the traction force, obtained during experimental runs on a railway section under various adhesion conditions. The article presents a technique for studying the wheel pair adhesion failure of electric locomotives with asynchronous traction motors.Results. During the comparison of the obtained experimental results with the calculated parameters by the O. Polach mathematical model, an updated range of the relative slip of wheel pairs is given, in which the electric locomotive control system could realise the maximum tractive effort. Exceeding this range will lead to increased wear of wheel pairs without increasing traction properties.Discussion and conclusion. It is advisable to use the results of the study in the future when developing systems for controlling the tractive effort at the limit of adhesion and systems for controlling the slip of wheel pairs of electric freight locomotives with asynchronous traction motors.

In 2022, the main testing centre of Russian railways, the Experimental Loop of the Railway Research Institute, turns 90 years old.The experience accumulated by the Experimental Loop is unique at a global scale: at the time of its creation, it was the world's first designated testing area for the latest models of railway vehicles and materials.The contribution of the Experimental Loop to the development of Soviet and Russian railways cannot be overestimated. A specially built proving ground and highly professional staff equipped with all the necessary tools made it possible to radically accelerate the development of new railway technologies and their implementation in the transportation process. The reputation and importance of the Experimental Loop is confirmed by the constant attention and visits of top state officials and industry leaders.The presented historical essay shows the main stages in the development of the Experimental Loop, as well as its significance both for the transport industry of our country and for Russian railway science.

Abstract: The article presents a diagnosis of the problems that affect the quality of the level training and examination of cyclists in Poland. The first part presents statistics on accidents involving cyclists in Poland in the recent years. The current system of training and examining cyclists as well as teachers and instructors is described successively. Additionally, examples of good practice that are used by countries with highly developed cycling culture are shown. Based on the assessment of the current state of affairs and the analysis of the issues, appropriate conclusions were drawn, and recommendations were proposed. They can contribute to the awareness of the need to change the approach in the Polish cycling education system and ultimately to increase the cyclist's sense of safety in road traffic, thus reducing the number of injuries and fatalities. Keywords: Cycling safety; Cyclist; Bicycle training; Training of cyclists; Examining of cyclists; Cycling education; Cycling licence; Cycling proficiency test.

Abstract: The article covers the possibilities of using modern IT and electronic solutions to modify the maintenance process of railway vehicles operated in the Warsaw metro. The legal and technical aspects of rolling stock operation were discussed, and examples of three types of vehicles used in the Warsaw Metro were presented. The current technical solutions in the field of monitoring the condition of some vehicle components were indicated. Keywords: Metro; Rolling stock; Maintenance system

Abstract: Work on and in the vicinity of active railway tracks or other tracks is particularly hazardous work. They involve high risks for workers who may be hit or run over by moving rail vehicles or track machinery. Workers may also be electrocuted by the overhead catenary or overhead electrical network, which for non-traction purposes is supplied with 3000 volts DC. To ensure an adequate level of safety during this type of work, active tracks should be cordoned off and marked in accordance with railway regulations. Guidelines for securing the site of works carried out on closed track during the operation of railway vehicles on live track at a speed of V ≥ 100 km/h are defined in Railway Instruction Id-18. All types of construction work on live railway lines and overhead contact lines may only be carried out on the basis of the Instruction for Safe Work Performing (IBWR), which is an annex to the Safety and Health Plan (Safety and Health Plan). It is important to remember that the site protection systems used should be certified and approved for use on railway lines. Rail transport is a particularly demanding area in terms of safety. The key to increasing its level is to continue existing and take new measures to promote the idea of safety. Automatic Warning Systems are still an innovative solution in Poland, which has been successfully proven in Europe for several years and is a safer option for the railway signalman. The system is responsible for the safe warning of railway traffic in the area of the repaired and adjacent track. Risks arising due to human fallibility or caused by human error are eliminated to a minimum. Keywords: Technological solutions; Trackway; Railway line

Abstract: The paper presents the application of geogrids with uniform radial stiffness in subgrade structures in the function of protecting under ballast mats from damage caused by the railroad superstructure. The importance of the stabilizing function as a key mechanism of cooperation between geogrid and aggregate was pointed out, affecting the increase of subgrade bearing capacity, extension of ballast life and ensuring the required operating parameters of the ballast placed on anti-vibration mats. Keywords: Mechanical stabilization; Hexagonal geogrids; Under ballast mats; Railway trackbed

Abstract: The article presents the most important aspects of changes in the training and examination system for candidates for train drivers and train drivers, which will enter into force on January 1, 2023. First, the system currently in force in Poland is characterized and its basic disadvantages are indicated. Then, the scope of legal changes resulting from the amendment to the Act on Rail Transport is described, which will lead to the separation of training and examination processes, and, as a result, to improvement of the efficiency of these processes. The article also presents the scope of activities of the currently built Center for Examination and Monitoring of Train Drivers, which will function at The Office of Rail Transport and will be equipped with modern simulators. Keywords: Train driver; Training; Examination; Simulator

Abstract: Sustainable development, i.e. the coherence of economic and social progress with environmental protection, are goals that must be achieved in order to prevent global environmental degradation. Reducing the emission of harmful compounds and noise is a current problem raised in various sectors of the economy. Through the ICAO International Civil Aviation Organization, the aviation sector worldwide is committed to meeting its commitments to reduce air emissions from aircraft. Despite the dynamic development of the unmanned aerial vehicle sector, manned aviation remains the leading means of passenger and cargo transport in civil aviation. In view of the emission of compounds having a negative impact on the environment by airplanes, it was deemed necessary at the global level to take steps aimed at a real limitation of the functioning of aviation, which is destructive to the nature. The International Civil Aviation Organization (ICAO) has developed a program that introduces a new approach to reducing negative effects on the environment called CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation). The article presents the principles of its operation and implementation, as well as the project phases. The practical impact of the CORSIA program on aircraft operators and examples of costs for operators related to the implementation of the project were indicated. The aspect of mutual coexistence for the CORSIA program and the EU CO2 emissions trading system (EU-ETS) was also raised. European Emissions Trading Scheme - also known as the "Community carbon market" or the ETS. It is the first, by 2017, the largest and currently the largest, after China, CO₂ emissions trading system in the world. Keywords: CORSIA, EU ETS, CO2; Emission; Civil aviation; Sustainable development of aviation

Abstract: The process of verification of the installation of the ‘on-board control-command and signalling’ subsystem is complex and requires numerous and time-consuming checks of both the overall technical documentation for a given ETCS installation on a specific vehicle, as well as checks performed during in-service tests. The experience has shown that the tests carried out in laboratories in simulated conditions and the commissioning tests of the on- board and trackside subsystems do not provide sufficient certainty in terms of the correct integration of the ‘on-board control-command and signalling’ subsystem with ‘trackside control-command and signalling’ subsystem and other subsystems. Therefore, additional tests of ETCS (European Train Control System) and GSM-R (GSM for Railways) on-board configurations with trackside ETCS and GSM-R installations on railway lines were introduced (hereinafter ESC / RSC compatibility tests). The premise of the ESC compatibility tests and RSC is to facilitate the operation of new subsystems, because their correct functioning in a given environment is fully verified at the stage of demonstrating compliance of ESC and RSC. In accordance with Polish requirements, from 1 July 2021, ESC / RSC tests are obligatory for all new, renewed and modernized projects in the field of the ‘on-board control-command and signalling’ subsystem. This obligation is a big challenge for vehicle manufacturers and users, because at that time these tests had not yet been carried out on the network managed by PKP PLK S.A. Accordingly, this article aims to introduce the issues related to the ESC and RSC tests, as well as to describe the roles and responsibilities of the various parties involved. in the implementation of the tests. Keywords: ESC / RSC tests; Compatibility; ERTMS, ETCS