Analysis of the problems of mechanical gearboxes of transport systems and their solution using a magnetic sensor

Objective: Increasing reliability of mechanical gearboxes using a magnetic sensor, which will sig nifi cantly increase the reliability of transport mechanisms and systems in general. Methods: An analysis of incidents covered in the media was carried out. Results: Conclusions are drawn about the consequences of failure of mechanical gearboxes. To prevent emergency situations caused by a breakdown of a mechanical gearbox, it is proposed to use a magnetic sensor, which allows carrying out analysis and diagnostics of the gearbox and its components during operation. A mathematical model of a magnetic sensor is compiled and a block diagram of a device for processing the output signal of the sensor modulator is presented. Practical importance: Failure of a mechanical gearbox is a common problem that leads to a stop of transport mechanisms and systems. Detection of a mechanical gearbox malfunction can signifi cantly reduce the cost of repairs, as well as prevent unexpected damage to the mechanism, which can lead to a complete stop of the transport system. The use of a magnetic sensor in the traction gearbox of an electric train will reduce the likelihood of a traction gearbox breakdown during operation and reduce the cost of repairs, increase the reliability of the traction drive, and also simplify the commissioning of new electric trains and traction gearboxes.

Evaluation of the possibility of using alternative sources of electrical energy to power auxiliaries of traction substations of power supply divisions on the example of ECHE-20 “Bronevaya”

Objective: To assess the possibility of using alternative sources of electrical energy to power auxiliaries of traction substations of power supply divisions on the example of ECHE-20 “Bronevayaˮ. Methods: Alternative energy is used on the railways. Results: Equipment was selected and a solar power plant was designed, economic effi ciency from the introduction of an alternative energy source and its payback period were calculated. Practical importance: The designed alternative source of electrical energy makes it possible to increase the energy effi ciency indicators of production processes of railway transport

Influence of inaccuracies and measurement errors on frequency of uncoupling of cars for unscheduled repairs on the railways of the Republic of Uzbekistan

Objective: Considering the impact of inaccuracy and errors in measuring the thickness of the fl ange of wheelsets on the frequency of uncoupling for unscheduled repairs on the railways of the Republic of Uzbekistan. Conducting an analysis of the impact of uncoupling freight cars for unscheduled wheelset malfunctions repairs. Methods: Methods of combinatorial and statistical analyzes of the initial data are used. Results: A detailed analysis of car uncoupling for unscheduled repairs on the railways of Uzbekistan has been carried out. The probabilities of car uncoupling operation in TR-2 (current repair) due to the “thin fl angeˮ malfunction have been determined. The infl uence of inaccuracies and measurement errors on the frequency of uncoupling of cars for such a repair is estimated. Practical importance: The results obtained contribute to the deepening of knowledge about the possibility of the infl uence of inaccuracies and errors in measuring the thickness of the fl ange of wheelsets on the performance of cars.

Thermal model of an asynchronous traction motor of a diesel locomotive

Objective: Evaluation of the temperature regime of the windings of an asynchronous traction electric motor with a squirrel-cage rotor (ATED) of the DAT-350 type of a 2TE25A diesel locomotive using the de- Современные технологии – транспорту 467 ISSN 1815-588Х. Известия ПГУПС 2021/4 veloped thermal model. Methods: The research was carried out by the fi nite element method in the application for calculating steady-state temperature fi elds SolidWorks. Resuls: To ensure the specifi ed service life of the ATED, the temperature rise of the windings must be limited to safe values, based on the insulation class. Therefore, it is crucial that designers and operators have access to accurate and computati onally effi cient, physics-based ATED thermal behavior modeling tools. Practical results: Using the proposed methods, it is possible to accurately and effectively evaluate the thermal characteristics of ATED of promising diesel locomotives. In addition, designers can easily and quickly adjust the parameters and performance characteristics of the ATED in such a way that they are conducive to improving the overall performance of the locomotive.

Elastic characteristics of the underrail base of a ballastless railway track

Objective: Experimental determination track modulus and the coeffi cient of relative stiffness of underrail base and the rail, which are the main elastic characteristics that determine the stresses in the structural elements of track superstructure under the impact force from the train. The values of these parameters for a track with a ballast layer are well studied, in contrast to a ballastless track. Comparison of the elastic characteristics of a ballastless railway track with analogs of a track on ballast, as well as an assessment of their effect on the stress-strain state of the superstructure elements of a ballastless track. Methods: When carrying out full-scale tests, strain-gauge methods for measuring stresses in the elements of the track superstructure were used. The obtained values were processed by the methods of mathematical statistics. One statistical series included the values of stresses corresponding to one type of rolling stock, fi xed axle load and train speed, changing by no more than 10 km/h. The probability level in processing the results was taken in all cases equal to 0,994. Results: The values of track modulus and the coeffi cient of the relative stiffness of the underrail base and the rail were obtained for a ballastless structure of the RHEDA 2000 type. Practical importance: The results allow us to consider the rail as a beam lying on a solid elastic foundation in relation to the ballastless track and use the existing calculation methods for the design of ballastless track structures depending on the operating conditions.

Ways of improving the efficiency of capital investments into the infrastructure in order to adapt it to ensure accessible environment

Objective: Formation of a unifi ed approach and adaptation of infrastructure facilities through the prism of rational use of capital funds and through the principle of comparative advantage based on opportunity cost. Methods: The main tools of analysis and management, the principle of comparative advantage, dynamic changes, schemes graphical models describing algorithms or processes, etc. are applied. Results: An analysis of possible ways of capital investment is carried out, with the fi nal comparability of the conditions and amounts spent on the adaptation of the main functional areas and infrastructure elements, taking into account the principles of “universal designˮ and “reasonable adaptationˮ. Practical importance: The proposed model is dynamic and can be applied as a criterion for the effectiveness of investments, both for individual investment projects and for investment programs in the full life cycle, including the operational stage.

Organisational features in the work of a railway station complex during the launch of “Aeroexpress”

Objective: To consider the change in the operation of the St. Petersburg transport hub station and the railway station when launching the Aeroexpress. Methods: Means and methods of logistics, general theory of systems, terminalistics, system and economic analysis, as well as management of operational work of railways are used. Results: Alternative options for changing the operation of the station and the station at the launch of the Aeroexpress are proposed in the conditions of the St. Petersburg transport hub station. The fi rst option involves organizing the reception and departure of Aeroexpress trains on the existing track intended for suburban traffi c. The second option assumes to specialize for the reception and departure of fast suburban electric trains in communication with Pulkovo airport the existing apron electrifi ed receiving and receiving track in a complex with an island passenger platform located nearby. When passenger fl ows change at the station complex, the number of ticket offi ces is calculated. The issues of organizing service activities for servicing Aeroexpress passengers at the station complex are considered. Based on the economic calculations carried out and based on the results of the survey of potential Aeroexpress passengers, practical recommendations were made for launching an Aeroexpress train in the conditions of the St. Petersburg transport hub. Practical importance: The results obtained can be applied in the implementation of the concept of development of the St. Petersburg transport hub, in the design of individual elements and devices of the railway hub to improve the organization of passenger transportation, as well as in determining the prospects for the development of railway complexes.

Power supply for a CIP position for bearings

Objective: Two possible options for power sources are considered: a controlled three-phase bridge rectifi er circuit with a step-down transformer and a pulse converter receiving power from the network through an uncontrolled three-phase bridge rectifi er to drive the wheel-motor units of electric locomotives and electric trains into rotation with the required frequency at the position of CIP bearing diagnostics. In both cases, it is assumed that the power supplies receive electricity from the 380/220 V, 50 Hz network. The power source is loaded with traction motors of the ER2R, ER2T, ET2, ET2M electric trains and the VL-10 electric locomotive. Methods: Mathematical modeling is used in the MatLab/Simulink environment for analytical calculations. Results: The currents and voltages of the load were determined, based on the calculations, the control angles and power factors of the rectifi er with a step-down transformer, the duty cycle of the pulse converter. Practical importance: A variant of an energy-effi cient power supply is proposed, including an uncontrolled rectifi er and a pulse converter.

Determination of the required amount of traffic of suburban trains, taking into account all-day and intraday irregularities in passenger traffic distribution

Objective: Automation of processing data on passenger traffi c in an arbitrary direction in order to determine the number of “threadsˮ in the time schedule for suburban passenger traffi c in the future. Verifi cation of the adequacy of the existing infrastructure and design solutions for reconstruction in terms of ensuring the required throughput capacity of railway lines. Methods: The calculation of the number of trains is carried out by mathematical modeling of passenger traffi c distribution by hours of the day on each day of the week of the initial month. The identifi cation of trains with non-daily destination is made by comparing the calculation results for each day of the week. Results: An algorithm has been developed for calculating on a computer the perspective amount of suburban train traffi c, taking into account the uneven distribution of passenger traffi c by hours of the day and days of the week. Practical importance: The data obtained using the presented algorithm makes it possible to simplify the development of advance time schedules, taking into account the needs of the population in transportation. The results of the work can be used in feasibility studies for the reconstruction of station layout development and passenger devices, as well as serve as the basis for the technical re-equipment of lines in order to increase their throughput (replacement of signaling and communication equipment, construction of second main tracks, reconstruction of yard necks, etc.). The results of the calculation also make it possible to identify schedule “threadsˮ for withdrawal of trains on days of the week when they are not in demand, but at the same time take into account non-daily trains when developing a standard time schedule. The form of presentation of the results takes into account the spatial irregularity of passenger traffi c and makes it possible to distinguish zonal trains.

Optimization of control systems for suburban trains

Objective: The use of pulse conversion of electricity on direct-current traction rolling stock is discussed. Methods: A variant of the system for regulating the operating modes of traction motors of suburban electric trains using a pulse converter based on insulated gate bipolar transistors is described. (IGBT). Results: The proposed impulse control system is presented as a possible option for the modernization of the applied control systems, which makes it possible to improve the traction and energy indicators of suburban electric trains. The advantages of pulse converters based on IGBTs are shown in comparison with converters based on one- and two-operation thyristors. A simplifi ed electrical diagram of the power circuit of a motor car with a pulse converter is presented, a description of the operation of the power circuit in the traction mode and in the modes of rheostatic and regenerative braking is given. Practical importance: The presented results of the technical and economic comparison of the control systems of the ED4M electric train with a Современные технологии – транспорту 505 ISSN 1815-588Х. Известия ПГУПС 2021/4 contactor-rheostat control system and an electric train with regulation of the operating modes of traction electric motors by a pulse converter based on IGBT prove the best energy effi ciency of an electric train equipped with a pulse control system