When creating a new rolling stock or during its modernization it is important preliminarily to properly assess its operational efficiency, depending on the technical improvements. Changing the way of energy supply of traction is very important - for example, hybrid engines or two/three power units is used instead of one. The article proposes a new approach to the problem of assessing the effectiveness of operational work of shunting locomotives. Shunting operation is represented as the sum of random single modes, in which the processes in the power plant can be modeled with any degree of accuracy. Summation of performance indicators in individual modes according to the characteristics of random processes allows obtaining an overall assessment of technical and economic indicators of the locomotive in operation. The paper shows results of comparative assessment of the fuel economy of a diesel locomotive ChME3 in operating set of equipment and with installed electronic fuel injection control system (ESUVT. 02), obtained by modeling the working processes of the power plant and auxiliary equipment shunting locomotives in operation modes. Executed calculations show that in the operation of diesel locomotive ChME3 equipped with ESUVT. 02 system saves up to 10.2 % of fuel, particularly by reducing fuel consumption at idle. Application of a new methodology for assessing technical and economic indicators of locomotives in operation allows, in addition to fuel consumption, evaluating a number of other indicators.

Aerodynamic forces of current collector depend not only on the design parameters, but also on weather conditions determining the dynamic pressure. Currently, when conducting field tests, control of these conditions is not performed, this can affect the accuracy of the results. The objectivity of measurements can be provided by theoretical and experimental methods of accounting air density. A theoretical method based on the calculation of the density of air environment by using data about the temperature, atmospheric pressure and relative humidity in the area where tests of current collector was conducted. The experimental method involves the use of ultrasonic density meter of air. Density values, defined experimentally, increase the accuracy of the results due to the fact that registration takes place directly on the roof of the locomotive, where the current collection was performed. It is shown that the dependence of the vertical component of the aerodynamic forces of current collector from the air density is linear. The article also substantiates the necessity of taking into account the density of the air environment by comparison of results of tests conducted under various meteorological conditions. The method of data matching, in which there is a correction factor, is proposed and the densities are set to the value corresponding to the normal environmental conditions. Due to the lack of criteria in the normative documents for comparing two samples, set to normal conditions, it is proposed to use a statistical method - t-Student criterion. This method assumes a normal distribution of data samples, as evidenced by the results of field tests conducted earlier. Given method allows comparing the results of field tests and evaluating the quality of the current collection, not only under normal conditions, but also in the entire temperature range, relative humidity and atmospheric pressure, at which the current collector can be operated.

A brief analysis of the physical and mechanical properties of materials, used in the construction of the rail bed, has shown that in scientific and technical literature there is scattered unsystematic information obtained under different physical conditions for bulk materials (gravel and sand). Unstructured data on the physical and mechanical properties of granular materials does not allow formulating a relatively complete dynamic theory for a wide range of static and dynamic loads, vibration acceleration and humidity conditions in relation to rail transport. In this article the authors formulate the problem of stability of the system “clayey soils in the main area - protective layer of sand cushions - ballast crushed stone prism” under the impact of harmonic oscillations on the basis of physico-chemical mechanics. Loam or clay belongs to isotropic visco-plastic media, sand and gravel - to disperse granular media. Filling the pore space of the gravel with weeds leads to the retention of precipitation and melt liquid. During deflation processes clogging of the gravel layer is increased. Despite the enormous practical value, properties of granular materials, until recently, practically not been studied. Under appropriate conditions this material may behave as a solid and as liquid and as gas. Each phase has unique properties that distinguish granular materials from all other substances. If the vibration field is applied to layer of gravel or sand, the energy of this motion is passed even through individual granules. As a result, with sufficiently high amplitude of jitter a phase transition occurs: the entire mass of granular material gets in motion, begins to flow due to reduction in friction between the particles and behaves as a kind of “granular liquid”. Fluid state of gravel stone occurs at much large values of the amplitude of vibration because of its angular shape. The result is a hydrodynamic instability, then convection starts and the vortices spontaneously appear.

Currently Russia is in need of qualitative means of solving the urgent problems of transport sector, namely optimization of technological processes of production, an unacceptable level of labor losses, delays in passenger and freight traffic, an increase of energy consumption, negative impact on the environment, inadequate performance of transport system. Rail transport is currently developing a new stage of technical and economical development by using the results of scientific progress in technology, economics and engineering. And in recent years in Russia there were significant limitations of volume and quality characteristics of transport system. Prospective research and development in the form of modern technologies, equipment and services on the basis of the automated control systems and the organization of transportation process contributed to increased traffic on the railways. In this work authors propose organizational and management technique, organizing the structure of modern relations among participants of transportation process for low-density railway lines of JSC “Russian Railways” (hereinafter - low-density line). The aim of this study is to improve exploitation of infrastructure of low-density lines based on integrated assessment of its performance. One of the productive directions in addressing the problem of low-density lines in terms of restructuring of JSC “Russian Railways” is the development and implementation of methods of integrated performance assessment which allows assessing proposed management solutions for more efficient use of infrastructure and selecting optimal strategies for performance of low-density lines. Thus, research and development in the field of assessment of low-density lines operation as an objective tool for the analysis and organization of its performance is an urgent scientific challenge. Using the proposed method allows substantiating the feasibility of using infrastructure of low-density lines and consolidating joint efforts in the region, business entities and JSC “Russian Railways” to solve the problem in practice.

The objective reality of the modern conditions of track operation is a continuous increase in train mass. Retrospective analysis shows that the average weight of trains on Russian Railways for the period from 1940 to 2015 is increased from 1301 to 3960 tons. In 2015 weighting rate of trains on most areas of the network is set to 6300 tons, and in certain areas - 7100 tons, formed from cars with axle load of 25 ton/force. Creating high-power locomotives allows in certain areas, such as the Trans-Siberian railway, passing the trains with weight up to 9000 tons. The article discusses the impact of driving conditions of heavy trains (running in the maximum traction mode, locomotive braking and during coasting) on formation of track deterioration on operating section of trains, part of which included cars with higher axle loads of up to 27 ton. Researches was carried out at the Oktyabrskaya railway (direction Kovdor - Murmansk). It is found that the number of deviations in the track geometry at the Kovdor - Pinozero section before operating cars with increased axial loads in areas with traffic on the maximum traction mode were higher by about 1.5 times, and in the areas of application of locomotive braking by about 1.7 times higher than in areas with coasting motion. When cars with higher axle load were introduced into the operation the greatest negative impact on the criterion of track geometry deviations were subjected to areas with traffic at maximum traction mode, and especially the braking areas, where the number of deviations has increased relative to areas with coasting in 2 - 2.5 times (during summer months).

The paper presents the main results of comprehensive experimental studies on the determination of regularities of dynamic processes and actual values of the forces of interaction of wheels with defects on rolling surface and rails on the modern designs of the track, carried out at the experimental section of railway track. It was determined experimentally that: dynamic processes of interaction of wheels with defects such as flats, weld-on, uneven rolling have specific shape and phase marked by the geometrical shape of defects; dependencies on impact forces to the flat-type defects were approximated by a polynomial function with the highest levels of forces in the speed range of 50 - 70 km/h. For defects such as weld-on or uneven rolling marked by impact forces with increasing speed; all the above types of defects are marked by considerable variation of levels of impact forces for the same modes of running (speed, direction), which is connected with meandering nature of the movement of wheelset, determining differences in the interaction of wheel and rail; dynamic impact loads initiate pulsed total deflection of rail in the vertical direction and the horizontal transverse motion. Values of total vertical deflection reach 8 - 9 mm for the values of impact forces of 400 - 450 kN that is 3.5 - 4 times more than the quasi-static motion of rolling stock; dynamic impact impulse excites damped oscillatory processes in vertical and horizontal directions with decay time 0.1 - 0.12 seconds. The levels of vertical acceleration in the rails with impact forces of 400 - 450 kN reached 191 - 258 m/s. The spectrums of vertical oscillations dominated oscillations with a frequency of 6.4, 50 - 60, 90 - 110 Hz. The presence of high-frequency components is connected to the excitation of vertical vibrations of the rail-sleeper network. In the process of impact interaction rail oscillations with frequencies of 25, 75 - 80 Hz also developed laterally.

Current collection, while electric rolling stock is running, is a complex process. The quality of dynamic interaction is estimated at an average contact pressure of current collector and its standard deviation. To measure contact pressing force special equipment is used that is installed on the current collector and provides force measurements in contact “current collector-contact wire” with the required frequency. Obtained contact pressure measurement values are random variables that are affected by many factors, each of which is not possible to take into account simultaneously. Therefore, currently the most effective way to study the contact pressing is to carry an experiment. Preliminary check of obtained experimental distribution of contact pressure for normality was determined considering the basic static distribution parameters. Coefficients of skewness and kurtosis were calculated. To determine the nature of density of the experimental data distribution a histogram, as well as theoretical and experimental graphs of distribution density were built. Probabilistic values for evaluation of law of experimental data distribution are shown. Check on plausibility of the hypothesis about the consistency of theoretical and experimental distribution density was made, applying the criterion of Pearson agreement. The study on type of distribution of experimental value of contact pressing force of the current collector on the contact wire of catenary as a random variable showed that there are deviations from the normal law. Since the cumulative probability for the range ±2σ and ± 3 of normal distribution and the cumulative probability of contact pressure in the respective ranges differ by less than 1 %, in practice, to assess the quality of current collection it is permissible to use the average contact pressing of the current collector and its standard deviation.

At present there is a need to develop a method of braking calculations for rolling stock with antiskid devices. In other words, at the stage of designing the car (carriage) calculations must be produced proving that the planned parameters of antiskid devices will not let the car enter into skidding during braking, while providing sufficient braking performance. The article proposes a method of calculating antiskid devices of rolling stock in order to assess performance of antiskid devices with selected parameters for the carriage. The principle of the proposed calculation is that firstly a value of the coefficient of adhesion between wheel and rail should be determined, where the wheel will start to fail at a given speed of skid (critical adhesion coefficient). Then a value determined at which the adhesion brake factor on the wheelset (ratio of brake force to the axle load) of antiskid device will allow entering into skid with a given speed at the critical adhesion coefficient. This brake friction coefficient will be called valid, and its dependence on the speed - “antiskid curve”. The conclusion on antiskid devices is made by comparisons based on “antiskid curve” with the calculated (theoretical) dependence of the brake coefficient of friction of the car from the speed (adhesion curve of wheels and rails). The proposed approach makes it possible to compare the impact of various factors on the performance of antiskid devices and standardize the requirements for it. On this basis, it is expected to develop a methodology for rational use of antiskid device for a particular type of car. The proposed approach wasn’t used worldwide previously.

Freight rolling stock of Russian Railways is equipped with automatically operating brake control valves (BCV). BCV is complicated braking device directly engaged in the braking process and thus affecting the safety operation. In this regard the strict requirements established by the relevant normative documents are imposed to work of BCV. The article by the example of selecting perspective brake control valve from several options under consideration shows regular method based on a comparison in a particular case of 13 criteria that characterize the properties of different distributors from functional and economically feasible point of view. Number of criteria, as shown, does not affect the sequence of solutions, therefore, the number is not limited to these criteria. In addition to numeric values, conventional “weight” of criteria is considered reflecting the importance of its relationship with each other for this problem, allowing obtaining a qualitative result of calculation. The method can be successfully applied for an objective selecting of other complex devices of brake system (brake control valves for passenger rolling stock, antiskid devices, etc.), when the number of considered comparing criteria is large enough. Initial data when assigning criteria for the objective selection of the diffuser (a complex device having a mandatory fully determined and specific properties and meet the same specific requirements, including controversial) are applicable regulatory documents, publications, test results and other published materials.