Науково-дослідна частина УДУНТ
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Browsing Науково-дослідна частина УДУНТ by Author "Kozachenko, Dmytro M."
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Item Controlling the Speed of Rolling Cuts in Conditions of Reduction of Brake Power of Car Retarders(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Kozachenko, Dmytro M.; Bobrovskyi, Volodymyr I.; Grevtsov, Serhii V.; Berezovyi, Mykola I.ENG: Purpose. The study aims to develop the requirements for organization of the marshalling process in the conditions when the power of retarder positions is less than the nominal one. Methodology. The research is carried out using the train traffic safety theory and mathematical modelling of hump processes. Findings. The current technical standard documents regulating the operational performance of humps do not contain direct instructions on how to proceed in the event of brake power loss by car retarders, thus creating threats to the traffic safety. This problem is quite acute for the Ukrainian railways in connection with a chronic shortage of funds for the repair and renewal of technical equipment, including the humps. At the same time, a significant drop in the volume of work leads to the fact that the hump required processing capacity can be provided in case of partial failure of retarders as well. Herewith the most important task is to ensure the breaking-up safety in conditions of parametric failures of retarders. The analysis of dangerous situations, the occurrence of which is possible at humps, as well as the modelling of cut rolling, allowed establishing the connection between the value of retarder tire pressing force on the car wheels and the breaking-up modes, providing the safety of marshalling process. The paper sets the application areas of such measures as the breaking-up speed reduction, breaking-up termination, the use of additional braking by block hangers. Originality. The originality of the work lies in the fact that it first obtained the complex of dependencies that determine the performance requirements for the power of hump retarders and allow the staff to enter the appropriate limits for breaking-up modes to ensure the marshalling process safety. Practical value. The results of the research can be used to supplement the «Instruction on the maintenance of facilities of mechanized and automated humps» in order to determine the limits of breaking-up modes when detecting the reduction of retarder power below the nominal one.Item Creation of Export-Oriented Network of Grain Elevators in Ukraine(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Kozachenko, Dmytro M.; Vernigora, Roman V.; Rustamov, Rustam S.ENG: Purpose. The scientific paper highlights improving the efficiency of export rail transportation of grain cargoes in Ukraine by introducing shipper routing and concentration of loading at the terminal grain elevators. Methodology. According to the experience of the USA and Canada, one of the most effective ways to reduce costs in the grain to-port supply chain is a shipper routing of the rail traffic. Shipper routing for transportation of grain cargoes involves the concentration of their loading on the multiple junctions. The junctions are proposed to be selected with the use of cluster analysis methods. For the formation of the grain loading concentration areas the authors used methods of set theory and multi-criteria optimization. Findings. Based on agglomerative cluster analysis algorithm, the junctions on a network of Ukrainian railways are selected and the areas of possible concentration of grain loading are formed. DSU-algorithm allowed distinguishing the overlapping and non-overlapping areas of concentration. The problem of selecting non-overlapping areas of the grain loading concentration is formalized as the problem of multiobjective integer programming with boolean variables. The solution of this problem by a modified simplex algorithm allows selecting on the railway network of Ukraine 24 districts of possible grain loading concentration, which cover 70 stations and at minimal additional cost provide routing of about 7.5 million tons of grain per year. Originality. The originality of the work lies in the fact that the authors developed the mathematical procedure for selection of junctions and concentration areas of grain loading at the Ukrainian railway network, taking into account the economic efficiency of the process. Practical value. Application of the developed method of grain loading concentration for the formation of unit trains will significantly reduce the logistics costs in the supply chain of grain to Ukrainian ports for export and, consequently, increase its competitiveness in foreign markets.Item Especially the Functioning of Railway Stations in the Conditions of the Organization of Transport Dangerous Goods(Дніпропетровський національний університет залізничного транспорту ім. академіка В. Лазаряна, Дніпропетровськ, 2016) Kozachenko, Dmytro M.; Zhuravel, Irenа L.; Zhuravel, Vyacheslav V.ENG: Purpose. Ensuring a sufficient level of transport safety is an important task in the context of development of railway transport as a part of international transport corridors and under increasing freight traffic volumes. The intensification of the transport process when there is the significant depreciation of fixed assets actualizes the development and implementation of methods to of improving the safety of railway transportation of dangerous goods, as well as technological and organizational measures, which are directed decrease of risks of emergency situations with its goods. Methodology. The methods of system analysis and theory of the railways operating management were used. Findings. The regulatory framework of the dangerous goods transportation by rail was characterized. The main indicators of the dangerous goods transportation under modern conditions of railway transport functioning were investigated. A detailed structure of the factors, which influence on the stations operating conditions during the transportation of dangerous goods was developed, and the measures of the stations technology improving in order to increase the traffic safety were proposed. Originality. Authors had detailed features of the functioning of the railway stations functioning under the dangerous goods transportation management. Practical value. Taking into account the factors and implementation of the proposed measures will improve the safety level of dangerous goods processing at railway stations.Item Functional Simulation of Railway Stations on the Basis of Finite-State Automatа(Silesian University of Technology, Poland, 2014) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Vernigora, Roman V.ENG: The general scheme of railway station’s model and technique of formalizing the technologic processes at stations are described. To take into account the human impact on station’s operation is suggested to use ergatic models. In conformity with concept of stations’ ergatic models a person is directly involved into the simulation process and manages the station technological processes acting as a dispatcher. The formalization of technological processes for processing the objects is performed on the basis of deterministic finite-state automaton. Designed model can be used for optimization of technical and technological parameters of railway stations, as well as in computer simulators for training of railway traffic managers.Item Improving the Methods of Estimation of the Unit Train Effectiveness(Silesian University of Technology, Poland, 2016) Kozachenko, Dmytro M.; Vernigora, Roman V.; Balanov, Volodymyr O.; Sannytskyy, Nazar М.; Berezovy, Nikolay I.; Bolvanovska, Tetiana V.ENG: Summary. The article presents the results of studies of freight transportation by unit trains. The article is aimed at developing the methods of the efficiency evaluation of unit train dispatch on the basis of full-scale experiments. Duration of the car turnover is a random variable when dispatching the single cars and group cars, as well as when dispatching them as a part of a unit train. The existing methodologies for evaluating the efficiency of unit trains’ make-up are based on the use of calculation methodologies and their results can give significant errors. The work presents a methodology that makes it possible to evaluate the efficiency of unit train shipments based on the processing of results of experimental travels using the methods of mathematical statistics. This approach provides probabilistic estimates of the rolling stock use efficiency for different approaches to the organization of car traffic volumes, as well as establishes the effect for each of the participants in the transportation process.Item Probabilistic Approach for the Determination of Cuts Permissible Braking Modes on the Gravity Humps(Silesian University of Technology, Poland, 2016) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Dorosh, Andrii S.; Demchenko, Evhen B.; Bolvanovska, Tetiana V.; Kolesnyk, Anton I.ENG: The paper presents the research results of cuts braking modes on the gravity humps. The objective of this paper is developing the methods for assessment of braking modes of cuts under conditions of fuzziness of their rolling properties, as well as selecting the permissible starting speed range of cuts from retardant positions. As a criterion for assessing the modes of target control of cut rolling speed, it was proposed to use an average gap size on a classification track at the established norms of probable exceeding of permissible speed of cars collision and their stop in retarders. As a criterion for evaluating the modes of interval control of cuts rolling speed, using the risk of their nonseparation on the switches was proposed. Using the simulation modeling and mathematical statistics, the configuration of the range of permissible speed of cuts coming out from retardant positions has been set. The conducted researches allow simplifying the choice of cut braking modes in systems of automatic control of cut rolling speed.Item Researching Operation of the Railway Stations with Using of Their Ergatic Simulation Models(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2013) Bobrovskyi, Volodymyr I.; Kozachenko, Dmytro M.; Vernigora, Roman V.ENG: The general scheme of railway station’s model and technique of formalizing the technologic processes at stations are described. Designed model can be used for optimization of technical and technological parameters of railway stations, including with using the grapho-analitical method.Item Techno-Economic Evaluation of the Efficiency of Improvement of Techniques Rationing Fixing Rolling Stock on the Station Tracks(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2013) Kozachenko, Dmytro M.; Pasichnyi, Oleksandr M.ENG: Purpose. This is dedicated to evaluation of the efficiency of improvement of the advanced method of normalization of quantity of wheel chocks for fixing rolling stock on station tracks, which was proposed as a result of former study. Methodology. In this study the simulation modeling of station work is used for calculation of rolling stock downtime. The method of techno-economic comparison is used to evaluate the efficiency of improvement of the new method of rationing number of wheel chocks for fixing rolling stock. Findings. The effect of the proposed method to the conditions of work of the railway stations had been analyzed. It was revealed that the introduction of improved methods of rationing fixing rolling stock will lead to substantial savings in operating costs of the railway.Originality. The advanced method of normalization of quantity of wheel chocks for fixing rolling stock on station tracks is proposed at first, that’s why the techno-economic evaluation of its efficiency has also been made for the first time. Practical value. The result of this study shows that use of the advanced method of evaluation of wheel chocks number for fixing rolling stock will lead to savings in railway’s operating costs because of decreasing rolling stock downtime.