Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan

About: Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan is a education organization based out in Dnipro, Ukraine. It is known for research contribution in the topics: Track (rail transport) & Bogie. The organization has 736 authors who have published 655 publications receiving 1468 citations. The organization is also known as: Institute of Railway Transport Engineers.

The basing of stabilization parameters of a fortified railway bed

Abstract: Purpose. The article is devoted to stabilization parameters determination of reinforced railway bed. At the present time, the railway plays the leading role in transport system to ensure the needs of freight and passenger traffic. In modern conditions railway operation concentrates on ensuring the necessary level of track reliability, including the roadbed, this is one of the main elements of road structures. The purpose of this article is the determination of basic parameters of stress-strain state to stabilize the soil subgrade embankment by reinforced materials. Methodology. To achieve this goal the following tasks of researches were solved: the effect of reinforcing layer of geomaterial on deformation properties of soil subgrade in various design of strengthening was investigated, the distributions of stresses in the subgrade were determined, reinforced of geomaterials under state load. Experimental studies to explore the nature of the deformation model subgrade at various degrees of stress were carried out. Findings. The analysis of the results of performed experimental and theoretical studies permitted to do the following conclusions. In conducting researches determined the distribution of stresses in the subgrade reinforced geomaterials under static load. The complex of experimental studies allows exploring the nature of the deformation model subgrade at various degrees of stress. Originality. On the basis of the theoretical studies have been regarded the problem of determining the stress-strain state of subgrade reinforced geomaterials by measuring stresses in its application for step loads. Practical value. The practical value was presented by the results of evaluating the effect of reinforcing way for changing the stress-strain state of subgrade.

The results of analysis of experimental research parameters of the geotextile-reinforced ground

Abstract: In the article the results of analysis of parameters of experimental research of the geotextile-reinforced ground bed are presented.

Frequency determination of high-frequency link for percpective electric rolling stock

Abstract: Purpose . Total mileage of Ukrainian electric railways is distributed approximately equally between the areas of direct and alternating current. A double system of electric rolling stock is used to pass jointing places of different current kinds without train’s stop. Therefore introduction of such rolling stock of a new concept that is using an asynchronous traction drive is prospective for Ukrainian railways. Apart from advantages a rolling stock of similar concept has significant disadvantages, it is pulse energy consumption from the power supply, and it can affect the reliability of track automatic devices, and consequently, the train traffic safety. In addition the specific power of traction transformer is considerably inferior to the power density of other traction elements. The promising schemes using an intermediary link of increased frequency, which consist of a transformer and inverter, have been proposed for disadvantages amendments. The main task for the further introduction of prospective circuit is to determine the operating frequency for high frequency link. Methodology . The method of thermal parameters calculation of semiconductor devices has been used for determination switching transistors of maximum operating frequency. To obtain analytical expressions curves of energy, released during the IGBT (insulated-gate bipolar transistor) switching from its current load approximation method is used. Findings . The permissible frequency of lowfrequency link is determinated by load current of intermediate transformer. Operating frequency range of a link depending on load current has been determined. A comparative analysis of the switching characteristics of 65 class IGBT production by companies Infineon and ABB has been performed. Originality . The further determination method of the maximum operating frequency of intermediate link for circuit with high-frequency transformer has been developed. Practical value . The established operating frequency range of the highlevel link will develop further research of tractive circuit with highfrequency transformer use for double feed electric rolling stock with asynchronous tractive drive. It will evaluate the introduction effectiveness of similar configuration circuits.

Determining permissible speed of tilting train in curved track

Abstract: Purpose . The main purpose of the article is to determine the permissible speed of the air-cushioned tilting train in curved track and to justify the expediency of operating this type of rolling stock on the railways of Ukraine to increase the speed, improve the passenger comfort and save the energy due to more uniform high-speed train driving. Methodology . The determination of the maximum permissible speed of the tilted train in curved track involves the use of methods of linear and vector algebra and empirical formulas for applied scientific and technical research. The calculation of the maximum speed is based on the principle of calculating centrifugal force for the velocities that meet the safety criteria of movement on the horizontal unbalanced acceleration in the stable radius curve. Find ings . The results of the calculations showed that in the 1000 m radius curved track section, provided the passenger comfort, the maximum permissible speed of the train without forced tilt is 132 km/h, and with the forced tilt – 189 km/h. The velocity gain in the curve is about 30% and up to 10% on the section (depending on the number of curves). Originality. The method of determining the permissible speed of the tilted train in curved track is improved, which consists in determining the permissible centrifugal force acting on the train in the stable radius curve, taking into account the passenger comfort conditions. Practical value. This method allows accurately determining the permissible speed on the condition of passenger comfort in the curved section and the required additional tilt angle of the train, depending on the speed, curve radius and canting. Enhanced speed and comfort of passenger trains in the future will increase the demand for rail services among the population and strengthen the position of rail transport in Ukraine’s transport system.

Calculated volumes determination of work for main-line and industrial railway stations

Abstract: Purpose. This article aims to improve the evaluation of irregularity of freight transport and calculated volumes determination of work for railway stations and sidings of industrial enterprises. Methodology. The methods of mathematical statistics are used as research methods for estimation of calculated volumes of traffic and loaded traffic, in particular, the methods of time series analysis; the methods of mathematical modeling are used to evaluate the calculated volumes of empty traffic. Findings . Calculated volumes of the main-line and industrial railway stations activity are determined according to the monthly and daily irregularity. Monthly irregularity is proposed to evaluate against the trend of the indicator over the last 3-5 years, constructed using the method of weighted moving average. The 30-day period in the previous year with the largest total amount of work is proposed to use as the calculation period for the assessment of daily irregularity. The computation size of empty traffic volumes is proposed to be determined on the basis of loaded traffic volumes with the probability matrix of cars usage for dual operations. The proposed method is verified by the work volume calculation for the year 2014 according to previous time periods. The test results showed that the proposed method as compared with traditional one provides higher stability of the results when changing time periods, used for analysis, as well as a more accurate assessment of the calculated volumes of work. Originality. Authors have improved determination methods for the calculated volumes of work to railway stations through the using time series analysis methods. Practical value. The proposed methodology allows assessing more accurately the prospective volumes of work and, through this, reduce the amount of capital expenditures associated with the development of stations and operating costs associated with their operation. The method can be used to improve the governing and methodological documents regulating the design and development of technological processes of the main-line and industrial railway stations.