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RUSSIAN RAILWAY SCIENCE JOURNAL

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Vol 79, No 6 (2020)
View or download the full issue PDF (Russian)
https://doi.org/10.21780/2223-9731-2020-79-6

319-326 833
Abstract

Currently, a project for organizing the transportation of perishable freights by “Cold Express” trains is under development, which is a new transport product aimed at delivering food, agricultural raw materials and other highly profitable goods to cities where regular container trains are impractical. The article discusses the economic efficiency of the investment project for organizing the transportation of freights in regular refrigerated container trains on the example of the Vladivostok—Moscow—St. Petersburg route, taking into account the arrangement of at least 18 container sites capable of handling transit container trains. Transportation according to the “Cold Express” concept involves the delivery of freights on the Vladivostok— Moscow—St. Petersburg route to associated large cities by container train loaded with refrigerated and insulated containers, according to a developed schedule with a known arrival and departure time. Capacity of the freight transportation market on the pilot route of the “Cold Express” is 2.0 million tons with the development of transportation in both directions when reaching the design capacity. Freight traffic will be formed by 23 stops on the route, 2 port hubs, 2 border land crossings with a traffic size of 7 pairs of trains per week. As part of the project, an assessment was made of the need for the local reconstruction of passing stations and equipping them with new ones or refurbishing existing container terminals. At the same time, the commissioning of these terminals is supposed to be gradual within 7 years of the project, which also allows gradually increasing the freight base and improving the quality of transportation. The article presents the results of calculations of the commercial efficiency of the project for the Russian Railways as the owner of the infrastructure, carrier and operator of these container terminals, which show its high prospects. Even with an incomplete train load predicted due to uneven density of freight traffic, the net discounted payback period is 10 years.

327-336 505
Abstract

Usually, to study the vibrations of rail carriages, the equivalent geometric unevenness of the track obtained as a result of processing the records of the track measuring car is taken as a disturbance. Such a record contains a certain set of irregularity wavelengths, for example, 50, 25 and 12.5 m. However, when it is used to simulate disturbances at different operation speeds, these wavelengths will correspond to frequencies depending on the given speed of motion, which is not permissible, since a stable frequency range from 0.2 to 10 Hz is required to excite the vibrations of all the bodies included in the carriage. To eliminate this drawback, in the previously performed works it was proposed to generate a random process of geometric irregularities for a given operation speed by changing the set of wavelengths included in the irregularities. In this paper, based on the study of random oscillations of a simplified model of a rail carriage, as a system with one degree of freedom, the adequacy of the method for generating a random disturbance process is verified in two ways. In the first method, it was found that the characteristics of random oscillations of such a model, obtained in the time domain on the basis of numerical integration of the equation of motion when specifying the generated disturbance, have satisfactory convergence with similar characteristics found by the frequency method using Shannon's formula. In the second verification method, the cross-correlation function and the mutual spectral density between the disturbance and the bouncing oscillations were determined from the generated disturbance realization and obtained by numerical integration of the vibration process realization. Then, using the method of identifying the dynamic system, experimental amplitude and phase frequency characteristics were found, which showed satisfactory convergence with the corresponding calculated characteristics obtained by numerically solving the equation of oscillations of the model under study. On the basis of the results obtained, it was concluded that the considered method of generating a random process of disturbance is sufficiently adequate and that it can be applied to solve problems of the dynamics of rail carriages.

337-342 725
Abstract

JSC “FRITEX” has developed non-asbestos ridge composite brake shoes UR 01-01 with a reduced coefficient of friction, which, in contrast to the cast iron ridge brake shoes currently used on locomotives, have high wear resistance and more stable frictional properties at high speeds. They are much lighter than traditional cast iron shoes, resulting in lower logistics costs and easier replacement by service departments. However, the new materials used for the production of the shoe, as well as its innovative design, which combines the two types of materials, require a detailed study of its frictional properties. For this, the braking modes of a locomotive equipped with UR 01-01 shoes were simulated in a full-scale unit of a brake mechanism on an inertial stand at fixed pressures and speeds. Based on the results of the experiments, the values of the friction coefficients of the brake shoes were determined and the dependence of the friction coefficient of the shoes on the pressing force and braking speed was established. The data obtained were used in braking calculations for an electric locomotive of the VL80 series, including the determination of the braking distance, holding a single locomotive by the parking brake on a slope, and ensuring the antiskid braking due to higher values of the friction coefficient of the UR 01-01 shoe at high speeds. The composite ridge brake shoe ensures compliance with the standard values of the braking distance, antiskid braking and slope parking for the VL80 series electric locomotive. In this case, the use of these composite shoes is possible without changes in the device of the lever transmission of the electric locomotive. It is necessary to conduct running brake tests to make approbation of obtained empirical dependence of the friction coefficient of new shoes on the pressing force and the braking speed of the locomotive and its widespread use in the calculation of brake systems.

343-350 554
Abstract

The article is devoted to solving the problem of optimizing the tariff policy, which is relevant for the passenger complex, with the most rational use of the rolling stock. Principles of economic and mathematical modeling are presented in order to determine the optimal number of cars in passenger trains and prices for travel in a single calculation process called complex optimization. Developed models make it possible to form optimal train schemes in accordance with the predicted demand, balancing supply and demand for transportation, which, in turn, radically increases its economic efficiency. Simultaneously with finding the optimal schemes by the method of complex optimization, such fares are determined at which the balance of supply and demand is achieved with the maximum possible economic effect. The article discusses the analytical models of passenger demand, the principles of implementation of the complex optimization procedure, the problems of forecasting passenger demand and the features of calculating the forecast of demand for the example of train No. 17/18 “Karelia” on the Petrozavodsk—Moscow route, and also offers a solution to the problem of determining the optimal prices and train schemes. On the example of real data of the operation of this train, the effectiveness of the automated system for managing the profitability of passenger traffic, created on the basis of complex optimization algorithms, was evaluated. It is shown that the developed analytical models of passenger demand allow solving optimization problems that increase the efficiency of automated control systems for the economic indicators of the transportation process, and the multi-model forecasting system provides satisfactory accuracy with a high level of forecast detail. Due to the fact that the level of expenses for train journeys radically affects the result of optimization of the transportation process with variable train schemes, the adopted optimization criterion takes into account both income and transportation costs. The results of calculations are presented showing that the complex optimization procedure for the “Karelia” train could give a significant additional financial result.

351-359 765
Abstract

To increase the competitive advantages of rail freight transportation, the long-term development program of the Russian Railways provides for an increase in the speed of freight trains. The design speed of freight cars currently operating on the railway network is mainly 120 km/h, and the permitted speed is limited to 90 km/h. One of the possible solutions to the problem is the introduction of freight cars with an increased speed. At JSC “VNIIZHT” and JSC “VNIKTI”, work is being carried out on the selection of structures, the development of safety requirements, theoretical and experimental studies of freight traffic at increased speeds. In 2017—2018 at the Belorechenskaya—Maikop high-speed test range of the North Caucasian Railway, specialists of JSC “VNIIZHT” carried out running tests of a prototype of a platform car for transporting containers with a design speed of 160 km/h, developed by JSC “VNIKTI”. In the design of the platform car, a bogie is used, which is an analogue of the bogie of trailed cars of electric trains ED4 and ED9, with the selection of the stiffness of the springs in the spring suspension steps to comply with the difference in the level of the automatic coupler from the rail head in the “container” and “gross” modes. Analysis of the results of running tests allows determining the ways to improve the design of the bogie. To select design solutions for the purpose of ensuring safety, a review of the studies of domestic scientists aimed at studying the dynamic properties of railway rolling stock with various designs of the carriage part was carried out. Tests were carried out on prototypes of rolling stock having different elastic-dissipative connections in the “body-bogie-wheelsets” system. Based on the results of the analysis, design solutions have been determined that allow achieving satisfactory dynamic qualities for a freight car at a speed of up to 140 km/h. The adopted design solutions were tested on the basis of the results of theoretical studies of the dynamic properties of a platform car with a new bogie, carried out by the method of computer simulation. Increasing the flexibility of the spring suspension and the horizontal connection of the body with the bogie made it possible to improve the dynamic qualities of freight cars. To assess the safety during certification, it is required to develop a standard that would take into account the design features of car bogies, designed for increased speed.

360-364 593
Abstract

Delivery of perishable freights in proper quality essentially depends on the correct choice of a special vehicle and the correct calculation of the delivery time. According to the requirements of the Rules for the transportation of perishable freights by rail, all special vehicles by January 1, 2022 must obtain certificates of compliance with the standards established by the Agreement on the International Transportation of Perishable Foodstuffs and on special vehicles intended for these transports. This requirement applies to special vehicles used both in international traffic and for transport of perishable freights within the country. The article presents a brief classification of special vehicles used for the transportation of perishable freights. Formulas are given that allow calculating duration of transportation of such freights and average temperature of the outside air along the entire route. Procedure for choosing a special vehicle for the already known duration of freight transportation has been developed. It is concluded that the procedure proposed by the authors allows choosing the optimal special vehicle for the transportation of perishable freights. Using this sequence of calculations makes it possible to take into account the maximum number of external factors that affect the duration of transportation.

365-372 786
Abstract

The article substantiates the necessity of supplementing the existing estimate of the track position in the plan by the difference of adjacent bending arrows with an estimate of deviations from the fixed initial position, which ensures the constancy of the characteristics of a single-radius curve or the components of a multi-radius curve along their entire length. As a fixed initial position of the reference base (base position), it is proposed to accept the design position or the position of the track after the repair performed according to the project, and in the absence of the project, the calculated position obtained using verified programs. The question of determining the values of the deviation of the position of the curves at individual points from the base position and their ranking for different variants of recording the curves is considered. As possible options for surveying are considered Geodetic measurement methods using Cartesian and polar coordinate systems, methods of obtaining information from transformed data from sensors of track measuring cars, as well as the classical method of measuring the arrows of the bend of a curve.The article presents the results of calculating the indicators of the interaction between the track and the rolling stock (frame and horizontal transverse forces, lateral deflections of rails) when modeling the motion of a freight car along curves, the parameters of which were obtained on the basis of analysis of data from experimental sections. The calculation results are correlated with the analyzed data on the presence of deviations from the base position in the curves.

373-382 641
Abstract

Mass of a passenger train and, accordingly, number of cars in its composition is selected based on the amount of passenger traffic on the section, determined by the seasonal demand for transportation in each direction. In one direction of the section serviced by an electric locomotive, the mass of a passenger train may differ several times from the opposite direction, which depends on the destination station of the train and the period of its circulation. At present, in addition to 6-axle electric locomotives of the ChS2T and EP2K series, more powerful 8-axle electric locomotives of the ChS7 series operate in the same schedule for traction of passenger trains on railway sections electrified with direct current with a voltage of 3 kV catenary. All three series of the considered electric locomotives are designed for a maximum operating speed of up to 160 km/h. In this regard, there is a situation with the underutilization of the maximum speed and excess power of the ChS7 electric ocomotives, especially when operating with passenger trains of medium and low weight and a limited speed of 120 km/h. The comparative data on the specific power consumption of the EP2K 6-axle electric locomotives and the ChS7 8-axle electric locomotives operating in the same schedule, presented in the article, indicate the need to find additional reserves for saving the specific power consumption when servicing passenger trains of medium and low weight with ChS7 electric locomotives. The electric locomotive power system includes traction and auxiliary electric machines. The article discusses ways to turn off part of traction motors, which can be carried out with a standard electric locomotive circuit. However, when one section of the electric locomotive is turned off, the power of the four traction motors remaining in operation is not always sufficient to drive a passenger train according to the schedule. Therefore, a variant of improving the power circuit of an electric locomotive in the process of carrying out its overhaul is proposed. This option represents the modernization of the power circuit of the ChS7 electric locomotive when operating on a series-parallel connection with a pair of traction motors disconnected. As a result, the power circuit of the 8-axle electric locomotive operates similarly to the circuit of 6-axle DC electric locomotives with a collector traction drive. The expected savings in specific power consumption can reach 15% in comparison with the operation of an 8-axle electric locomotive ChS7 in normal mode. Switching off one section of the electric locomotive and further running the train on four traction electric motors will reduce the specific power consumption by up to 25%.



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ISSN 2223-9731 (Print)
ISSN 2713-2560 (Online)