Petersburg State Transport University

This article examines geodesic domes in the far north using different materials (wood and steel) to determine the most effective material based on cost. The main thesis of the article is that, depending on the material selected for the frame of a geodesic dome, using the SCAD calculation and graphic complex, it is possible to determine the necessary sections to ensure the bearing capacity for the first and second groups of limit states, which in turn will allow comparing structures based on their cost criteria. The article draws attention to possible ways to optimize the cost of building geodesic domes in the far north. The SCAD calculation and graphical complex of geodesic domes with a grating frequency of 8 V, made of different materials (wood and steel) under the same operating conditions, to find the optimal design based on the cost criterion.

Introduction . Concrete and masonry structures constitute the majority of old buildings in use. The aim of this research is to propose a methodology for assessing the seismic resistance of the cross-sections of elements ofconcrete and masonry structures. This research developes the previous research results in this area, which began in the USSR in the early 1980s. Materials and methods. The methodology of assessing the maximum accelerations and design seismic resistance classes for concrete elements of building structures is considered. For concrete elements the seismic resistance class is assessed by the position of the resultant force in the section (limitation of concrete tension) and by compressive stresses in concrete. The minimum seismic resistance class is assessed under the assumption of elastic work of the section. At the first stage, three values of the calculated peak accelerations are assessed, ensuring the following: the elastic work of the section, the limit state with the limit state coefficient К 1 = 0.5 and the limit state with the limit state coefficient К 1 = 0.25 respectively. Results. Basing on the resulting accelerations, one can assess the intensity of the design earthquakes using the Russian Standard scale of earthquake intensity. Conclusions. Basing on the research results, the authors assessed the intensity and repetitiveness of earthquakes resulting in various limit states of concrete and masonry structure sections, including the occurrence of section tension, the appearance of various cracks, complete section unloading, the appearance of spalls in the compressed zone of concrete, etc. These data are of interest to both facility owners and insurance companies.

Introduction. The article is devoted to the study of the current state and development trends of the national market for transport and logistics services in rail transport, represented by both the structural divisions of JSC “Russian Railways” and independent transport companies. Materials and Methods . Materials from open sources on the internet were used, along with methods of comparative analysis and statistics. Results. Based on statistical data, an analysis of the current state of the national market for transport and logistics services in rail transport has been conducted, identifying bottlenecks, the impact of external factors, and assessing the competitiveness of the industry. The main problematic issues and trends in the development of the national market for transport and logistics services in rail transport have been considered, as well as the tasks facing the country’s economy in the current geopolitical situation as a whole: import substitution, development of production, and therefore domestic freight transportation, reorientation of trade relations from the West to the East, building and developing new supply chains, digitalization of transport and logistics services, and establishing seamless logistics. Conclusions. The competitive advantages of rail transport in providing transport and logistics services are the ability to organize mass transportation of significant volumes of goods over long distances, the ability to provide shippers with the required types of transport vehicles, and the comprehensiveness of the services provided, while investments are needed for the modernization of infrastructure, renewal of rolling stock/containers, and digitalization of logistics processes.

Railway transport as one of the most important industries influencing the economic development of the country is interested in a constant inflow of qualified personnel. Increasing the attractiveness of educational programs of railway specialties requires a convincing demonstration to students of the availability of highquality education and compliance with production realities. One of the mechanisms determining the compliance of the educational process with the requirements of the labor market is professional and public accreditation (hereinafter — PPA). This article considers the role of professional and public accreditation as a tool for assessing the quality of education, which has undergone a significant stage of development over the past decade. The objects of the analysis are scientifi c publications devoted to this topic, data of federal statistical observation and authors’ analysis of the experience of conducting PPA in educational organizations of the railway transport industry. The role of PPA as a link between employment and education is revealed. The influence of PPA on various aspects of the educational organization’s activity is analyzed. The main tendencies of PPA procedure among educational organizations of the railway transport are determined. Branches and structural subdivisions of Universities of railway transport are prepared for independent assessment of education quality in the form of PPA. It demonstrates readiness for continuous development of the implemented educational programs.

The deformation method for the structural analysis is recognized as more accurate and reliable, as it is based on experimental deformation diagrams of materials (concrete and reinforcement). However, in practice, there are still no detailed examples of calculating the crack resistance and rigidity of bending reinforced concrete elements using a deformation model, despite its convenience and the ability to quickly obtain results through iterative procedures. Purpose : The aim is to calculate deformation of crack resistance and rigidity of bending reinforced concrete elements (service limit state), using design parameters obtained from calculating the deformation strength of the structure (ultimate limit state). Methodology : The study is based on initial data and design parameters obtained in the strength calculation. The methodology includes the following steps: determination of the crack formation moment by summing internal forces, arising from normal stresses in each small section; calculation of the distance between adjacent cracks, taking into account the tensile zone in the limit state; calculation of the crack opening width depending on stresses in tensile reinforcement. Determination of the element deflection taking into account the maximum curvature calculated using the deformation modulus. The paper also presents the adopted assumptions and prerequisites, theoretical formulas with respect to calculated ultimate strains and stresses (including the strain modulus). Research findings : A practical calculation example was performed, and a comparative analysis was conducted, calculating the percentage difference in between the deformation and standard (limit state) methods. Value : The novelty of the paper lies in the algorithm development for practical calculation of the crack resistance and rigidity of bending element based on the deformation model for the structural analysis.

Background. The article provides an overview of the current state of the railway container transportation market. Statistical data on the container transportation market is presented and analyzed. The article provides an overview of the work aimed at improving the organization of container transportation by rail. A generalized scheme of container delivery using rail transport is developed. The key objectives aimed at ensuring the reliability of container delivery are identified, and the main factors affecting the speed of container delivery are systematized. A mathematical expression of the delivery time of a container for the conditions of a direct option of transshipment from one mode of transport to another and taking into account the processing and storage of cargo at the terminal. Formulated the problem of optimizing the delivery scheme of containers in multimodal transportation in the conditions of the presence of several options of container terminals, their location. At the same time, according to the conditions of the formulated task, one processing of containers at the terminal is provided. A decision support system for changing the method of transportation of container products in multimodal transportation is proposed. Conclusions are drawn about the prospects of using the proposed system by transport and logistics companies. The purpose is to identify options for ensuring the flow and uninterrupted movement of container flows during multimodal transportation. Methodology. The article used an analysis of the current situation in the field of container transportation, mathematical modeling of container delivery time, optimization of the container delivery scheme based on the decision to overload the container at each terminal, and formulated a decision support system for delivery management. Results. The state of container transportation involving rail transport is determined, the analysis of studies in the field of container transportation using rail transport is performed, the directions of ensuring the reliability of container delivery are identified. A decision support system for multimodal container transportation is proposed. Practical implications. The results obtained can be used in the railway container transportation system, as well as by freight forwarding, operator, and transport and logistics companies.

Purpose: To evaluate current strategies for enterprise development in order to determine their viability under sanctions pressure. To develop recommendations for a sustainable long-term strategy that will be appropriate for a volatile external economic environment. To enhance methods for strategic planning. Methods: Analysis and synthesis, comparative analysis, economic and statistical techniques, along with expert evaluations. Results: The current strategic development approaches have been analyzed. The repercussions of saPurpose: To evaluate current strategies for enterprise development in order to determine their viability under sanctions pressure. To develop recommendations for a sustainable long-term strategy that will be appropriate for a volatile external economic environment. To enhance methods for strategic planning. Methods: Analysis and synthesis, comparative analysis, economic and statistical techniques, along with expert evaluations. Results: The current strategic development approaches have been analyzed. The repercussions of sanctions on the national economy have been thoroughly examined. Recommendations for establishing a sustainable long-term strategy in a volatile external economic environment along with effective strategic planning tools applicable across various enterprises have been formulated. Practical significance: Employing a scenario approach to evaluate the current enterprise strategy will enable the formulation of a comprehensive strategic development plan for industrial enterprises, factoring in the risks and uncertainties associated with sanctions pressure. Representing the development strategy as a “Decision Tree” will facilitate the visual identification and analysis of the enterprise’s strengths and weaknesses, thereby enabling the formulation of the most effective strategy for the enterprise’s advancement.nctions on the national economy have been thoroughly examined. Recommendations for establishing a sustainable long-term strategy in a volatile external economic environment along with effective strategic planning tools applicable across various enterprises have been formulated. Practical significance: Employing a scenario approach to evaluate the current enterprise strategy will enable the formulation of a comprehensive strategic development plan for industrial enterprises, factoring in the risks and uncertainties associated with sanctions pressure. Representing the development strategy as a “Decision Tree” will facilitate the visual identification and analysis of the enterprise’s strengths and weaknesses, thereby enabling the formulation of the most effective strategy for the enterprise’s advancement.

Purpose: To examine the life cycle characteristics of single-point and double-point tram track switches under comparable operational and installation conditions. Methods: An analysis of the volume of fundamental maintenance tasks performed on different switch designs over an identical duration, ensuring adherence to technical operational standards. Results: The findings indicate a reduced maintenance requirement for double-point switches compared to single-point switches within the same observation period, even when subjected to increased operational loads. Practical significance: The practical implications of this research are significant, particularly given the widespread use of single-point switches in Saint Petersburg and other urban tram networks. Establishing the economic viability of maintaining a specific switch design directly influences the overall life cycle cost, thereby providing a basis for evaluating the efficacy of different switch types in the design and operation of tram systems.

To evaluate the impact of long-term deformations caused by concrete creep and shrinkage on the stress-strain state of the rigid column-superstructure joint in a frame bridge. To verify the applicability of modern creep and shrinkage models for this type of structure. Methods: The numerical modelling was performed using the Finite Element Method (FEM) in the Midas Civil software. Nonlinear long-term eff of concrete creep and shrinkage, as well as prestress losses in the reinforcement, were considered. Results: It was established that concrete shrinkage exerts the most signifi infl on longitudinal deformations and on forces in the joints during the early service stage. Concrete creep partially compensates for the stresses induced by shrinkage. The most signifi changes in forces occur within the fi year of service; thereafter, the rate of change decreases substantially. The research results have confi the necessity of accurately accounting for long-term deformations in design. Practical signifi The presented results will enable a more accurate prediction of the rigid column-superstructure joint behavior in frame bridges, thereby reducing the risk of crack formation and elevated residual stresses. This will contribute to enhanced reliability and durability of bridge structures.

Monitoring the condition of traction electric motors (TEM) in locomotives involves diagnosing and predicting malfunctions. This has been a subject of a great amount of research. Accurate diagnoses and early detection of potential issues lead to timely maintenance and reduce downtime of locomotives at depots. This paper explores the use of TEM insulation diagnostics by analyzing partial discharge intensity. Methods: In recent years, a significant amount of research has been conducted to create new methods for monitoring the condition of TEM, addressing the shortcomings of traditional diagnostic techniques. Specifically, there is a shift from scheduled preventive maintenance to maintenance based on the actual operating condition of the equipment. The implementation of this approach significantly enhances the role of technical diagnostics. This paper presents an analysis of the experimental data obtained regarding changes in the partial discharge intensity during the diagnosis of the TEM insulation condition. Results: An ideal diagnostic procedure should include the essential measurements required to assess the condition of the machine. Based on the analysis of the data obtained, a diagnosis should be formed that enables an evaluation of the current state of the equipment, the timely identification of emerging failure modes in the shortest possible time. The research has shown that partial discharge currents are absent below a specific initial voltage. However, a certain degree of nonlinearity in the load gradation may still be observed even at voltage levels below this value. Practical significance: Reducing maintenance costs and preventing unplanned downtime of locomotives is a priority for manufacturers and operators. The implementation of advanced monitoring and diagnostics systems for traction electric motors will enable the development of rational proposals for improving the design of electric locomotives and enhancing their reliability during operation.