Introduction. The authors view methodology disadvantages for the calculating the existent traffic capacity of the single track analytically by defining the limiting space interval. The current calculation methodology does not fully consider the factors influencing the traffic organization. Thus, this method implies that all trains or pairs of trains evenly distribute the traffic capacity does not corresponding to the real situation. Railway sections should have some reserve capacity that provides carriage in condition of actual traffic volume.

Materials and methods. The authors proposed a new approach for determining the traffic capacity by the situation modeling through the alternate graph of train traffic and in accordance with various factors effecting the traffic capacity. Moreover, the authors carried out a comparative analysis of the transportation process indicators. They used two variants of the interval control system — automatic and semi-automatic blocking — in irregular traffic conditions.

Results. The performed simulation modeling demonstrates that the use of semi-automatic blocking train interval control does not secure the planned train traffic capacity through the single-track designed line in difficult climatic conditions.

Discussion and conclusion. The automatic blocking is considered more appropriate for the train interval control system. The mentioned blocking will provide not only the required capacity, but also the possibility of diagnosing the state of the trackway integrity. It is an important issue providing train traffic safety at low temperatures.

Introduction. The currently applied system of passenger and suburban train traffic in the Russian railway transport does not completely consider the passenger satisfaction of the provided service quality. The authors suggest determining whether supplements of the existing quality assessment method of passenger and suburban traffic are reasonable in terms of the arrival, departure, running schedule and considering the passenger satisfaction of the existing train traffic.

Materials and methods. The researches proposed the concept of “passenger dissatisfaction of the provided service quality in terms of passenger and suburban train traffic” (or “rate of passenger dissatisfaction of the train schedule implementation”). The passenger and suburban trains with the schedule deflection should be rated by the weighting coefficient of significance. It is necessary to consider not only train capacity and delay duration, but also the purposes of the trip and technological factors of the train running.

Results. The authors determine the numerical value functional of the delayed passenger and suburban trains. Moreover, the authors identify both the initial value of the train capacity and the train delay and the corresponding coefficient of the passenger dissatisfaction growth. The article presents requirements to the studies concerning the rate of passenger psychological sensitivity to the train delays. The developed model allows conducting the necessary research for the quality assessment system of passenger and suburban train traffic.

Discussion and conclusion. The solution of the presented problem is important both for the protection of passenger interests and for maintenance and improving of the railway transport image. In addition, the detailed solution will minimize losses in goods traffic while passenger and suburban train commitment to timetable.

Introduction. The rail-to-earth transition resistance is an important parameter of electrified railways, which directly effects the electrical safety level of the traction network and the potential distribution in the upper structure track area. The increased potential adversely effects the operation of the power supply system, the safety of passengers and service staff. Moreover, the mentioned potential leads to the insulation damage of the signaling equipment and to the threat of the train traffic security. The high-speed traffic development in Russia involves the ballastless track usage. The transition resistance of the ballastless track differs from that of a ballast track.

Materials and methods. The article considers mathematical model of the ballastless track for determining the rail-toearth transition resistance. The authors presented a description of the method for rail-to-earth transition resistance with a known input resistance of the rail track, determined experimentally.

Results. The paper demonstrates relative values of the voltage drop on the the ballastless track structural elements. The obtained data will be used to analyse and calculate the modes of operation of the traction power supply system that occur in the rail track during short circuits in the traction network, and to assess the electromagnetic compatibility of electrical installations.

Discussion and conclusion. Obtained results will lead to study the transition resistance of the ballastless track concerning high short-circuit currents drainage from the rails by simulating a short circuit both near the traction substation and away from it.

Introduction. The purpose of the research is to evaluate transition resistance modifications of the upper structure track in passing from the ballast to the ballastless track. These modifications effect the rail-to-earth potential difference. Moreover, they refer to the reverse traction system, to the reverse traction current of railway automation devices and to the required level of electrical safety guarantee.

Materials and methods. The authors used both the analytical method of the rail-to-earth potential testing and the practical one based on experimental studies of the rail track transition resistance measurements. The authors carried out experiments on the Rozengartovka — Boitsovo — Bikin section of the Far Eastern Railway. This section includes the heavy freight traffic with the increased electric resistance of the track ballast by the upper structure redevelopment.

Results. The research defines the main criteria of the rail-to-earth potential considering the 2×25 and 25 kV reverse traction of monophase AC systems with the 50 Hz frequency and depending on the experimental area location in terms of traction substations, on the climate and geological factors and on the freight traffic density.

Discussion and conclusion. The obtained results will improve the accuracy of the rail-to-earth potential difference considering not only indicated factors, but also the upper structure type, track features and a feed line scheme for contact wire.

Introduction. The development of power semiconductor devices and technology served the basis for fundamentally new types of frequency-controlled electric drives with traction asynchronous motors on the rolling stock of electrified railways. Therefore, problems of theoretical and experimental study of the operating modes of the mentioned drives become actual. This article is a theme continuation of the asynchronous machines control on the AC locomotive, which was presented in no. 5 of Russian Railway Scientific Journal in 2021.

Materials and methods. For analysing the frequency converter operation, the authors used mathematical modeling methods, which allowed evaluating the motor operation in various modes without resorting to time-consuming full-scale tests. Recently, software packages for visual programming have been developed, aimed mainly at domestic users, which are not inferior in their capabilities to leading foreign counterparts. Among such software products is SimInTech software for modeling technical systems, developed by 3V Service. The software focuses on solving various applied problems, particularly, on modeling a vector control system for an asynchronous drive.

Results. The authors developed a mathematical model of an asynchronous drive of auxiliary machines of an electric locomotive in a rotating coordinate system d – q by the SimInTech application package and concerning the cross-impact influence of d and q control channels.

Discussion and conclusion. The developed complex of an asynchronous motor and a vector control system enable to work out various algorithms for improving the energy efficiency of the operation of asynchronous auxiliary machines of an electric locomotive by applying the proposed algorithm for choosing the optimal value of the rotor flux linkage. The presented vector control structure also enables to implement it on the basis of modern microcontrollers, helping to reduce programming time.

Introduction. The authors analyse the problem of implementing regenerative braking on the AC locomotive with a monophase reversible voltage converter.

Materials and methods. The article consided theoretically possible options for the operation of monophase reversible voltage converters during regenerative braking, in which: 1) the reactive component of the electric locomotive current had a capacitive nature, and the operating current of the electric locomotive was ahead of its reactive component; 2) the reactive component of the electric locomotive current had an inductive nature, and the current of the electric locomotive was ahead of its active component. The research demonstrated that the former was only theoretically possible, since the regeneration of current into the contact network was carried out at a very low voltage, significantly less than the lowest voltage on the current collector. The latter was technically feasible in terms of the main harmonic of the electric locomotive current lagged by an angle exceeding of 90 electrical degree, but noticeably smaller than 180 electrical degree. Regenerative braking with a power factor close to unity was possible only theoretically, but in practice a power factor of 0.8–0.9 should be realized. The tangent of the angle between the effective current and its active component was greater (for a certain margin) than the quotient from dividing the active by the inductive resistance of the traction network between the electric locomotive and the traction substation. Moreover, it was necessary to consider the technological reduction of the ohmic resistance in the process of the monophase reversible voltage transducer control (e. g. over the deterioration of contact wire).

Results. The article demonstrates the possibility and conditions for the regenerative braking implementation on AC locomotives. Hence, a more advanced electric locomotive current control system with an additional channel for regulating the inductive component of the recuperation current is recommended for development.

Discussion and conclusion. An advanced control system stabilizes the current collector voltage and with the channel for regulating the active component of the regeneration current provide for the voltage maintanance at a higher level, determined by the actual electrical parameters of the contact network and the train traffic.

Introduction. The article discusses the energy parameters of electric power storage systems for DC and AC traction power supply systems. The purpose of the research is to evaluate the energy parameters of electric power storage systems located within the inter-substation zone boundaries of the AC traction power supply system at the 25 kV voltage.

Materials and methods. The author used the methods of modeling, statistics and the experimental results processing. Moreover, the paper presented the parameter estimation of the energy accumulation system on the basis of the traction calculations for the AC rolling stock. In addition, the author made two variants of calculations — in the presence and the absence of the electric storage system. The researcher also made the simulation of the electric storage system for the voltage source connected to the sectioning post busbars.

Results. Using the simulation modeling, the author presents active and reactive power graphs of the inter-substation zone boundaries in the active sectioning post operation conditions. Therefore, the article demonstrates the graph of the expected charge, the discharge depth calculations for the nominal energy capacity and the required charging features, which guarantee the charge restoration of the accumulation system to the initial level.

Discussion and conclusion. The author offers the comparative assessment of the electric storage systems for the traction power supply with the DС voltage of 3 kV and the AC voltage of 25 kV. The research demonstrates the reducing potential of the nominal accumulation parameters.

Introduction. The manufacturers currently develop new locomotives considering operating conditions with further locomotive fixation on the target ground. They also calculate the operational locomotive models with the key indicators for assessing the cost of the life cycle during the engineering stage. Therefore, the basic information for making operational decisions on purchase about selected locomotive items is the evaluation of the traction rolling stock effectiveness. The manufacturers of other vehicle types have similar aims in terms of operating conditions, engineering features, etc.

Materials and methods. The scientists succeed in the usage of the modern evaluating approaches to the vehicles efficiency. The application of the similar criteria that differ in the calculation mechanism and the initial data volume is especially important in evaluating the effectiveness of the multimodal transportation of freight and passenger traffic. The article presented the critical analysis of the main approaches to assessing the effectiveness of the road, water and railway vehicles. Thus, the authors concluded that the manufacturers should consider both the efficiency of the vehicle and the usage intensity.

Results. The authors demonstrate quantitative estimates of the proposed efficiency criterion for certificate features and considering real operational conditions. The paper presents the simulation results comparison with the calculation ones considering certificate features. Thus, operational conditions significantly effect the efficiency criterion.

Discussion and conclusion. The authors highlight that the obtained results are universal for evaluating the effectiveness of the various vehicles in terms of different rolling stock features.

Introduction. The article covers the approaches to assessing the efficient functioning of the modern upper structure track and aims at developing these approaches in the process of using the track superstructure materials — rails, fasteners, sleepers, ballast — under given operating conditions.

Materials and methods. The authors proposed methodological approaches for assessing the effective functioning of the modern upper structure track. These methods were based on the life cycle cost measurements of railway complex technical systems. The methodological approaches enable to consider the expenditures for the acquisition, possession and disposal of the upper structure track materials by discounting the cost indicators and the initial period value.

Results. The authors present the results of test calculations for assessing the effective use of ZhBR-65PShM, ZhBR-65Sh, ARS-4, Vossloh W-30 rail fasteners types on a 12-kilometer nominal section of the continuous welded rail with DT350 rails and a traffic density up to 80 t.km gross/km per year. The most efficient upper structure track option is the one, which has the lowest value of unit costs per 1 t.km gross and covers the full life cycle of the railway track section operation.

Discussion and conclusion. The developed methodological approaches will be used to evaluate, compare and select the most efficient upper structure track schemes under given operating conditions.