Rolling contact-fatigue damages of rails along with their wear are the most common types of rail defects. In recent years, there have been significant changes in the distribution of rolling contact fatigue damages of rails especially on railways operating under heavy haul conditions.

This paper is devoted to the overview of approaches to modeling of the occurrence of rolling contact fatigue (RCF) damages on working surfaces of rails. Four types of such approaches to modeling are considered. The first is based on the methods of contact mechanics. To realize it, the vehicle movement on the characteristic sections of the track is modeled, the forces acting in contact are determined, the contact problem is solved, and the values of the linear criterion of contact fatigue damage are determined. The required characteristics of rolling contact fatigue of the rail material are established on the basis of laboratory tests. The second approach uses the diagram of the adaptability of rail material to cyclic loads, proposed by K. Johnson, established on the basis of laboratory tests. The third approach uses criteria that have the physical meaning of the energy released at the contact as an index of the product of the tangential force in contact and relative slippage. In the fourth approach predicting the accumulation of plastic deformation under conditions of cyclic loading is performed on the basis of a series of standard tests of rail steels, including in the welded joint zone, and finite element modeling. In addition, there is also a probabilistic model, based on the assumption that it is possible to transfer the results of the RCF damage of rails on the experimental section of the road to any other site.

As the conclusion the authors formulated directions for further studies on the formation and development of surface rolling contact fatigue defects in rails.

With the increasing loads on the axle and speeds, the increase in wear resistance and resistance to contact fatigue of the wheels is of particular importance. In part, this result was achieved using a standard profile according to GOST 10791–2011 with the use of more efficient spring suspension. A further reduction in the wear rate of both the rolling surface and the flange can be achieved by developing a new wheel profile.

The authors have developed a technique that allows, based on theoretical calculations and experimental observations, to make the choice of the shape of the wheel profile, consistent with the profiles of the rails. The results of measurements of the wheels of cars of the model 12-9853 installed on bogies 18-9855 were used as the initial data, which were under controlled operation. The profile development consisted of four main stages: the choice of baseline data, the choice of the curvature of the rolling surface, the choice of the curvature of the transition section to the throttle, and the choice of the flange thickness and radius of the throttle in the transition zone to the rolling surface.

The technique was used to develop a new wheel profile that differs from the profile according to GOST 10791–2011 in that the rolling surface is made with three conjugate radii, respectively from the wheel to the flange: 500, 325 and 87.5 mm. The flange throttle radius of the developed profile is 17 mm, the angle of inclination of the flange to the horizontal is 68°, and the thickness of the flange is 32.5 mm. A part of the wheel surface from the wheel to the outer part of the rim fully complies with GOST 10791–2011. Calculations showed that the contact zone of the wheel with the VNITsTT profile relative to the rail is shifted from the center to the flange and the contact area is larger. It was found that for the VNITsTT wheel profile the ratio of the semi-axes of the ellipse of contact spots is lower than for the profile according to GOST 10791–2011.

Energy efficiency of transportation process is constantly in the center of attention of specialists and managers of Russian Railways. Some of the new electric locomotives purchased under the investment project have shown unsatisfactory results on electric power consumption. According to the management of the JSC “Russian Railways”, electric locomotives EP20, designed for two types of current, have the highest specific energy consumption. These are modern electric locomotives with powerful asynchronous traction motors. Electric locomotives typically operate in passenger traffic. The purpose of the research was to analyze the accounting of energy consumption of passenger electric locomotives in the locomotive operating depots. The article provides results of a comparative statistical analysis of primary materials on the energy consumption of passenger electric locomotives EP20 and other series of electric locomotives such as EP2K DC and EP1M AC. According to the primary materials from the locomotive operational depots, it was found that passenger electric locomotives with trains of double-decker passenger cars have the highest specific energy consumption. Comparison of specific electric power consumption by electric locomotives with single-type passenger cars showed that with DC electric traction, the consumption level of the EP20 significantly exceeds the consumption of the electric locomotives EP2K; with an AC electric traction, the flow rate of the EP20 is almost equal to the specific electric power consumption of the EP1M electric locomotives. A comparative analysis of the load of EP20 electric locomotives during the maintenance of passenger trains allocated for it in the Moscow — Adler section showed that the electric locomotive was underloaded, which causes a decrease in its efficiency and, as a result, over-consumption of electricity. The use of high-power brake resistors will lead to energy consumption, which must be taken into account in the life cycle cost of EP20 electric locomotives.

The paper gives comparative characteristic of a continuously adjustable and stepwise adjustable (switchable) filter-compensating installations (FCI) in the traction network of AC railways. Technical and economic calculations were carried out to increase throughput and reduce electric power losses. Effectiveness of switchable FCI is substantiated, taking into account features of traction.

Feasibility of using regulated FCIs at the traction network at the partitioning station is mainly determined by the need to increase the railway capacity by increasing the voltage on electric locomotive current collector, as well as due to the reduction of electric power losses in the traction network and in the external power supply system.

Efficiency of increasing the carrying capacity of the voltage in the traction network is determined by the maximum power of the FCI, and if these powers in the continuously adjustable, stepwise adjustable and unregulated units are equal, then the effect in increasing the carrying capacity will be the same. The effectiveness of reducing power losses in the traction network when using FCI installation at a partition station is generally limited, firstly, by the fact that electric locomotive is distributed throughout the entire inter-substation zone and, secondly, electric locomotive current is distributed between the partitioning post and the traction substations, and therefore FCI can compensate for only part of the electric locomotive current. This explains the limited possibilities in reducing power losses in the traction network of continuously adjustable FCI.

As a rule, in most cases, according to the operating experience of domestic traction power supply, the nominal power of FCI at the partitioning station is 3–5 Mvar. In the future, as the traction load increases, its capacity will increase to 7–10 Mvar. With an increase in the power of FCI over 10 Mvar, one should consider a distributed system of FCI in the inter-substation zone.

It is shown that the experience of regulated FCIs in the traction network of domestic railways indicates the need to develop a standard version of an economically adjustable unit, and the development can be based on the option of switchable FCI presented in the article.

The paper provides test results of pilot sample of resonant single wire transmission system to a distance of 2000 m at a higher frequency. Cable power lines used as the power line based on coaxial cable. Operating principle of resonant single-wire transmission system is based on the use of two resonance transformers with frequency of 5–15 kHz, wire line voltage between the line is 1–10 kV when operating in a resonant mode. Resonant power transformers consist of a resonant circuit and step-up/step-down winding. Resonance system for high efficiency energy transfer system when adjusting all parameters at certain voltage, frequency and load. With the set of equipment, which operates at a frequency of 7–9 kHz and at a voltage of 980 V, power line can transmit electricity on a single transmission line up to 3000 watts.

The article describes the possibility of applying a resonant sin-gle-wire power transmission system at a frequency of about 7 kHz for the transmission of electric power up to 3 kW from a stationary power supply system (three-phase voltage is 380 V AC, 50 Hz) for single-phase load, and earthed on the individual earthing inverter.

Efficiency of resonant single-wire electric power transmission system increases with increasing load capacity. It can reach 88–91 % directly at the maximum load with efficient conversion equipment.

Measurements of electromagnetic fields from unscreened power lines were carried out. The results of the measurements show that the maximum value of the alternating electric field in the frequency range of 2–400 kHz is 100–150 V/m, well below the maximum permissible level. The advantage of the resonance system compared to a single-phase system is in operating at the frequency of 7 kHz.

High proportion of electric trains with collector trac-A monitoring system of electrodynamic braking has been develotion motors in the multiple unit fleet and its low cost in comparison ped with preservation of the electric train standard equipment. It al-with electric trains with an asynchronous traction make it neces-lows regulating the recuperative current depending on the possibility sary to improve the control system of motor collectors. One of the of its consumption by changing the resistance of the braking resistors. ways is to create devices to improve the efficiency of recuperative Imitation model of DC electric train power circuit in the electrobraking. dynamic braking mode with a monitoring system was developed.

It takes into account the influence of eddy currents in the motor frame, armature current ripples and the catenary voltage increase during recuperative braking.

Electromagnetic processes in the electric train power circuit are investigated. Analysis of the obtained oscillograms shows the change in the armature current and the catenary voltage within the specified limits in the braking mode. Recuperative current regulator is tuned to an aperiodic transient with a time equal to 0.015 s.

The paper shows possibility of the monitoring system to regulate the armature current in the recuperative mode together with the automatic braking control system in case of increasing the catenary voltage. When the voltage fails, the monitoring system is not able to limit the increasing braking current, its reduction is effected by the magnetic flux of the traction motors.

Adjusting characteristic and the technical effect from the implementation of the monitoring system are calculated. The possibility of reducing the electric power consumption by 4.62 % is shown.

The article provides calculations of coefficients of polymer damping pads with elaborated materials that ensure minimal impact on soils under railway trackside and exclude its subsidence in a wide operating range of temperatures and frequencies. Application of additional metal plate between the pad under the rails and the pad on a sleeper was substantiated based on the theory of wave processes, that allows reducing amplitude of vibrational waves in rail and wheel by six times due to reflection in reversed phase at the “rail metal — polymer” border, and reduces the amplitude of the wave by three times due to reflection of vibrational waves in the “metal plate — pad — concrete sleeper” segment. Considering Russian extreme continental climate thermoplastic elastomers are recommended to use as under-rail pads, and polyurethanes for sleepers. An aluminum plate should be installed to increase damping factor between lining and pads. Such a composite lining can be operated at extremely low temperatures from –60 °С, and high to +80 °С. Significant amount of rubber and polyurethane pads is produced worldwide for different climatic and operating conditions. After conducting accelerated tests author suggests a transition to two or three types of “thermoplastic elastomer — metal — polyurethane” composite pads in order to unify a variety of different types of polymer pads according to the operating conditions, the material and construction used.