Dynamics of the Rolling Stock and the Choice of Parameters of Vibration Dampers

Modern railway rolling stock should meet requirements regarding comfort (maximum travel speed with minimum vibrations of wagons, noiselessness of movement, etc.).To eliminate the influence of dynamic loads, rolling stock is equipped with vibration dampers. The objective of the work is to select the parameters of the vibration dampers of rolling stock, depending on its characteristics, to ensure the due indicators of comfort and safety of transportation of passengers and goods by rail. To achieve this objective, applied methods of mathematical modelling were based on numerical programming of operation of dynamic systems. The indicators of vibration dampers are evaluated according to the results of studies of the dynamics of the rolling stock (in particular, of vibration protection rates).Assessment of dynamic state of the rolling stock implies application of methods of mathematical and physical modelling, which include the development of a physical and mathematical model, a calculation algorithm, and computer programming. The study of the mathematical model by numerical methods makes it possible to carry out a multifactorial experiment using a large number of input parameters (factors) and to select the characteristics of vibration dampers that are optimal for the conditions under consideration.To solve dynamic problems, the harmonic perturbation model, which is the most widespread, was specified in the form of a sinusoid with a period corresponding to the rail length.A quantitative assessment of the vibration process (frequency, amplitude) makes it possible to identify the main processes occurring in the system under consideration under various types of external load. The introduced assumptions related to rigidity, mobility and geometric immutability of the system allow determining the methods for obtaining a mathematical model and considering the vibrations as flat ones.The equations were solved in MathCad Prime 4.0 package using the Runge–Kutta method with automatic step selection. The subsequent study of the properties of the dynamic system was carried out by changing the resistance parameter of dampers of the first stage of spring suspension, while recording the values of the amplitude of the vibrations of the system and the period.The analysis of the results has shown that the vibration period of the body and bogies under any changes in the resistance parameter of the damper remains unchanged, while rational parameters of resistance of axle box dampers have been revealed for specified indicators. Hydraulic vibration dampers with the revealed parameters used on rolling stock help to reduce wear and damageability of running gears, improve ride comfort and traffic safety, as well as to reduce repair and maintenance costs.

Locomotive Reliability Assessment Method

The authors describe the analysis of the current state of the problem under consideration. A definition of "averaged failure flow parameter" is given. The periods of traction rolling stock life cycle are considered. The assumption of event distribution laws exponentiality is introduced, which makes it possible to obtain expressions of the main reliability indices in the analytical form. The work of depot service locomotives to ensure the required reliability and readiness of the rolling stock during their normal operation has been assessed. The introduction of the term "readiness" into the modern practice of traction rolling stock reliability estimation is considered. The initial data for calculating the indexes of locomotive uptime and readiness are presented. Calculated values of readiness and no-failure indices of electric locomotives in operation are obtained. The calculated values of internal and technical availability coefficients are compared with similar indicators established by technical specifications. Control procedures were performed to determine the compliance of each set of locomotives (EP1, 2ES4K) with the uptime requirements. As a result of comparing the calculated values of internal and technical availability factors (for electric locomotives EP1 and 2ES4K with analogous values set by specifications (EP1 and 2ES4K) it was determined that the surveyed locomotives comply with the established availability requirements. As a result of control procedures to determine the compliance of each set of EP1 and 2ES4K locomotives with the uptime requirements, it was determined that the set of 2ES4K electric locomotives for the run in question does not fully comply with the uptime requirement. And the set of EP1 electric locomotives meets the reliability requirements, but the error value is higher than 20%. To clarify both events, it is necessary to increase the mileage interval of the locomotives and repeat the procedure for determining compliance with the uptime requirements. The method of assessing the uptime and readiness of locomotives during their normal operation makes it possible to identify existing shortcomings in the operation of rolling stock and to form measures to improve the quality of rolling stock operation.

Estimation of strength properties of functionally graded structures with elliptical stress concentrators

Purpose: The purpose of this paper is to elaborate new calculation schemes for evaluating the strength parameters of railway rolling stock parts with non-local properties of surface layers in the presence of elliptical stress concentrators. Design/methodology/approach: Using the proposed approaches of developed mathematical modelling and open software for calculating FEniCS, it were established the most dangerous angles of stress concentrator orientation and the required thickness of the hardened zones of parts, which ensures their minimum softening during operation. Findings: It is shown that for an elliptical stress concentrator with any orientation angle, there is a certain key size of surface hardening thickness, the exceeding the value of which does not have influence on the operational strength of the parts, but rise the price of technological operations. Research limitations/implications: In this paper proposes a method for computation the impact of the orientation of the surface elliptical stress concentrators on the contact strength of parts under conditions of dominate friction power loads. Practical implications: The obtained results were used to set the modes of plasma hardening, which increase the contact strength of railway parts with elliptical stress concentrators. Originality/value: Using the approaches of contact mechanics, mathematical and computer modelling, methods of controlling the contact strength of the parts with the surface elliptical stress concentrators were proposed for the first time.

State of open wagon body when loading on a rotary car dumper

The use of modern means of mechanization of loading and unloading operations in places of mass processing of bulky loads in railway and water connection allows to increase the efficiency and productivity of various types of transport, to ensure the safety of load and rolling stock. The most common method of unloading open wagons in ports, mining enterprises, thermal power plants, etc. is the use of special rotary car dumpers. However, it should be noted that unloading on the car dumpers leads to damage of the carriages structural elements. The article presents the results of strength calculations of the car dumper body under the influence of specified dynamic loads from the expiring cargo. They show that the safety margin of the load-bearing elements of the car body is not enough at critical corners of rotation of the car dumper rotor. The studies were carried out using modern computer modeling methods used in the development of new-generation freight car designs. The software package took into account the effects of dynamic loading as external factors that occur at different corners of the car dumper rotor. The implementation of the results obtained at the design stage of innovative structures of open wagon car bodies will allow predicting the operational parameters of load-bearing structures. The presented studies are aimed at improving the safety and operational reliability of the cargo car fleet.

Fuzzy logic methods in assessing the transport and warehouse complexes functioning quality

In most sectors of the national economy, technical facilities are represented by unloading devices that extract bulk cargo from the freight rolling stock, store it for a certain time, and ship it to a similar or other type of transport. Objects intended for the implementation of the stages of loading, unloading, and various storage periods, including bulk cargos, are commonly referred to by the broad scientific community as transport and warehouse complexes (TWC). Most operations performed in the TWC are the movement of goods (internal movements, receiving or sending goods by various modes of transport. The authors clarified the concept of "transport and warehouse complex" - it is an element of the transport network of the region, providing communication of external transport systems of the regions and performing the functions of converting the cargo flow of the region into the cargo flow sent by the region. On the one hand, they perform functions of transshipment points in relation to deep (economic) warehouses, and on the other – the functions of storage facilities. Their primary purpose is determined and depends on a large number of factors, including: the size of the direct service area, the ratio of the design capacity of the warehouse to the volumes of deliveries and the use of bulk cargo, as well as the condition of roads in the serviced area, the uniformity of the receipt of bulk cargo and the availability of vehicles for their delivery to the consumer.

Organization of coordinated functioning of various types of passenger transport in transport-interchange hubs

The article deals with the organization of high-quality interaction of various types of passenger transport in the transport- interchange hub. Urban and regional interchange hubs are being studied. A methodology based on the use of quantitative methods and implemented with the help of software products (the developed program "Effective transfers" and the well-known simulation modeling programs PTV Visum, AnyLogic) is suggested. This method is applicable for any city and includes 3 stages. At the first stage, the number of passengers in the transport-interchange hubs who transfer from one type of urban public transport to another is predicted; the direction of passenger traffic is determined; urban routes that require schedule approval are chosen. At the second stage, the number of passengers who use the considered transport-interchange hub to transfer from suburban, intercity transport to urban modes of transport is predicted. At the third stage, the schedule of all types of transport is coordinated; the need for rolling stock is determined; passenger traffic is modeled and studied at the hub in order to rationally organize the planning structure of the transport-interchange hub. The obtained scientific results can be used in the design of a system of transport and transfer hubs and planning the placement of transport and social facilities on the territory of the transport-interchange hub.

Rationing of fuel consumption based on identification of rolling stock modes

The article presents the results of a study of innovative technology on improving the rationing of diesel fuel consumption on rolling stock in the railway industry. As an object of research, fuel consumption was studied on a Automotrisa diesel editing - ADE-1, which is used in the electrification and power supply facilities of the Transenergo Directorate. Motorized carriage loading transport (MLT – 6), which is used in the economy of the track. On the basis of a number of regulatory documents of the Russian Railways company, the Samara State University of Railway Transport was entrusted with the analysis of the efficiency of fuel consumption of SSPS on these types of rolling stock at one of the railway landfills. The special self-propelled rolling stock of the Russian Railways company was studied as an object of research. The method of forming fuel consumption standards by identifying the actual values of fuel consumption and indicators of rolling stock operating modes is considered. The statistical methods used in the research allow us to set the rate of consumption in the range of 8% of the actual flow rate. Based on the use of the obtained fuel consumption rate, a method for identifying and evaluating the level of unauthorized fuel overspendings (draining) is provided.

Reducing Power Losses by Voltage Stabilization at the DC Rolling Stock Current Collector

The invention relates to an energy-efficient method for voltage stabilization at the electric rolling stock current collector through traction substation control means which provide a nominal voltage value during the electric train movement by an interstation section. The dependence of potential distribution in the contact wire during the electric rolling stock movement by an interstation section was investigated. Also researched and developed are the new ways of voltage stabilization at the current collector of the electric rolling stock based on synchronous (the same for two adjacent traction substations) and asynchronous paths of voltage regulation at DC buses of traction substations related to one synchronous and two asynchronous ways of voltage stabilization in the contact network with obtaining the energy performance describing them. The energy performance of the investigated methods of voltage stabilization in the contact network is compared, and the energy efficiency of each of them is determined. It is proved that the use of modern types of semiconductor converters such as an active rectifier – voltage source in the power equipment of DC traction substations will enable to implement adaptive voltage stabilization systems at the rolling stock current collector, providing nominal voltage values of traction motors on the interstation section without using additional equipment on the rolling stock and, as a consequence, justification and application of these methods is suitable for upgrading the existing and designing new traction substations.