Science and Transport Progress

Cylinder Block and Cylinder Liners of Internal Combustion Engines: Materials and Features of Defect Detection During Repair

V. V. Krivda, I. H. Olishevskyi, V. E. Olishevska — Thu, 11 Dec 2025 00:00:00 +0200

Purpose. The main goal of this study is to review and systematize the materials and defects of the cylinder block and cylinder liners of internal combustion engines (ICE), as well as to analyze the issues and current trends in defect detection during repair. Methodology. The main problems currently associated with the defect detection of cylinder blocks and liners of ICEs include the following: the rapid growth of motorization, which leads to an increase in the number of cylinder blocks and liners requiring defect inspection; the use of manual labor, which makes the defect detection process labor-intensive and costly; the need for classification of defect types and their automatic recognition; the consideration of operating conditions influencing defect development; the necessity of implementing new defect detection processes; the need for quantitative wear assessment and prediction of component residual life; the adaptation of inspection methods and evaluation criteria to new materials. The study employs the following research methods: theoretical analysis (classification, systematization), review and synthesis of known scientific results, and empirical methods (comparison, observation). Findings. The authors conducted a review and systematization of structural materials and the main defects of cylinder blocks and liners of ICEs. The main issues in modern defect detection were identified as follows: insufficient process automation, low accuracy of visual and instrumental inspection methods, limited adaptability of existing inspection techniques to new materials, and the need for quantitative evaluation of component residual life. The development trends in defect detection systems are defined as the transition to automated and computerized inspection technologies, the creation of databases of typical defects, and the development of algorithms for predicting the residual life of components. Originality. The scientific novelty of this work lies in a comprehensive approach to analyzing structural materials, defects, and modern trends in defect detection of cylinder blocks and liners of ICEs. Materials used in component manufacturing have been systematized, a defect classification has been proposed, and the factors influencing wear intensity and defect formation have been identified. The trends in the development of defect detection systems have been established toward automation, increased sensitivity, and higher inspection accuracy. Practical value. The conducted analysis contributes to improving the efficiency of defect detection and repair processes of cylinder blocks and liners of ICEs, as well as to the development of informational databases of typical defects and the conditions under which they occur.

Research on Innovative Materials for Automobile Repair

V. E. Olishevska, H. S. Olishevskyi, H. P. Ivanova — Fri, 26 Dec 2025 00:00:00 +0200

Purpose. The main purpose of the work is to study the influence of innovative materials for car repair on the structure and properties of friction surfaces of parts and the possible mechanism of interaction of materials in tribological pairs. Methodology. The following research methods were used in the work: theoretical research (classification, systematization), analysis and generalization of known scientific results, empirical methods (comparison, observation), experimental research (metallographic analysis, microhardness testing, wear resistance testing, surface roughness measurement). Findings. Innovative materials based on serpentinites are proposed. The development is based on the ideas of using new-generation materials and controlling the processes occurring in the contact zone of friction pairs to increase the wear resistance and durability of tribological combinations. Experimental studies of the mechanism of interaction of innovative materials with 40ХН steel under friction conditions have shown that the hardness and wear resistance of the surface layer increase by 3 and 4 times, respectively, and the roughness of the contact surfaces decreases by 6 times. The components of innovative materials diffuse into the surface layers of friction surfaces and form metal-ceramic layers, which are solutions of the components of the studied materials in the phase components of 40ХН steel. The proposed innovative materials not only reduce the wear of friction surfaces, but also restore the functional condition of worn surfaces without interrupting the operation of mechanisms. Originality. The use of innovative materials to prevent wear and restore the functional condition of friction surfaces of automotive parts has been substantiated. The mechanism of action of innovative materials has been established, which consists in the directed ion diffusion of components of a special tribological composition. The mechanical and operational properties of 40ХН steel have been studied, and it has been established that an increase in the hardness of contact surfaces in combination with low roughness leads to a unique anti-friction effect. Practical value. Studies of wear processes and the formation of wear-resistant layers under the influence of innovative materials allow us to formulate conditions for treating friction surfaces to reduce wear, strengthen surfaces, and restore the functional state of worn surfaces without stopping the operation of mechanisms. Technological methods for introducing innovative materials into friction units have been developed, allowing high-quality wear-resistant layers to be obtained on friction pair surfaces.

Increasing the Capacity and Interference Immunity of the Data Transmis-sion Channel in the Automatic Cab Signalling System

K. V. Honcharov, R. V. Rybalka, V. V. Malovichko — Mon, 15 Dec 2025 00:00:00 +0200

Purpose. Improvement of the automatic cab signaling (ACS) system by increasing the capacity and interference immunity of the data transmission channel based on the rail line. Methodology. To achieve the purpose, the analysis of existing solutions for improving the automatic cab signaling system has been performed. The comparative assessment of capacity the data transmission channel in the automatic cab signaling system ALSN with numerical coding and the potential capacity of the channel based on the rail line has been carried out. The system of commands of the multi-valued ACS has been proposed, that in addition to traditional ALSN commands, allows transmitting to the locomotive information about speed limits at stations, permanent restrictions according to the characteristics of railway sections, as well as information about the current train situation on the section, taking into account the possible increase in speeds to 250 km/h. To increase the interference immunity of the data transmission channel, it was proposed to use Fire code and quadrature phase shift keying QPSK. The generator polynomial of the Fire code has been determined, the information rate and transmission time of one command have been calculated. Findings. To study the interference immunity of proposed system, the simulation model has been developed, the program code of which is written in Python. It was determined that the Fire code (12,6) is guaranteed to detect all errors except for quadruple, sixfold and eightfold. To eliminate such errors, it is proposed to perform multiple receiving of each command. According to the simulation results, the total non-detection coefficient for single reception is 0.0087, for double reception is 1.6·10^-5. In the case of triple reception, no errors were detected during the simulation. Originality. The authors of this work proposed a set of solutions for improving the continuous system of automatic cab signaling: increasing the source entropy; reducing information losses by using the error-correcting Fire code and quadrature phase shift keying; increasing the frequency of message transmission and multiple receiving. Practical value. The implementation of the proposed solutions will allow increasing the capacity and interference immunity of the data transmission channel based on the rail line, expanding the ACS command system taking into account speed limits at stations, information about the set speed for high-speed railway lines, as well as permanent restrictions in accordance with the characteristics of railway sections.

Level-Based Classification of Electromagnetic Effects in Certification Tests of Electric Rolling Stock

A. V. Zubko — Fri, 19 Dec 2025 00:00:00 +0200

Purpose. To develop a conceptual framework for interpreting the results of electromagnetic compatibility (EMC) certification tests of electric rolling stock using a multi-level classification system. The study aims to establish a structured method for distinguishing different states of electromagnetic influence based on measured parameters of amplitude and duration, thereby improving the representation and understanding of test data within existing certification procedures. Methodology. Existing approaches to electromagnetic compatibility testing and data interpretation in railway applications were analyzed to identify limitations in differentiating levels of electromagnetic influence. A structured method for precise classification is proposed, based on normalized comparison of interference characteristics. The developed framework defines transition zones between safe and potentially critical operating conditions and allows flexible adaptation of threshold parameters depending on test conditions. This ensures compliance with certification requirements while enhancing the diagnostic depth and informativeness of the results. Findings. A multi-level classification system for electromagnetic interference has been developed, providing a comprehensive representation of EMC test results. The approach enables identification of transitional states and trends toward critical operating conditions that are not detectable under a dichotomous evaluation scheme. It allows a more accurate interpretation of test outcomes, supports early diagnostics of instability, and provides a quantitative basis for assessing the operational resilience of railway systems. Originality. A systematic, multi-level framework for interpreting EMC test results of electric rolling stock has been developed. Unlike conventional methods limited to threshold verification, the proposed approach accounts for the dynamics of parameter variations and their interdependencies, enabling predictive analysis and a more complete understanding of electromagnetic behavior under various operating conditions. Practical value. The developed methodology enhances the accuracy, transparency, and reliability of certification testing for electric locomotives, multiple-unit trains, and other electrically powered rolling stock. It contributes to safer and more efficient railway operation by providing engineers and certification authorities with a comprehensive analytical framework for assessing electromagnetic compatibility. The approach is applicable for optimizing design solutions, refining certification criteria, and supporting the modernization of railway infrastructure.

Mathematical Modeling of the Neutralization Process of An Aggressive Impurity in Groundwater: An Express Model

M. M. Biliaiev, V. V. Kozachyna, O.Yu. Gunko, V. M. Kuznetsov, O. V. Zvonarova — Tue, 23 Dec 2025 00:00:00 +0200

Purpose. One of the modern means of protecting groundwater in the presence of aggressive impurities is the use of permeable barriers (reactive barrier). When conducting design work, it is important to determine the effectiveness of permeable barriers in advance. To solve such a complex problem, it is necessary to have specialized mathematical models. This paper considers the development of numerical models for calculating the process of neutralizing an aggressive impurity in the groundwater flow using a permeable barrier with regard to the flow hydrodynamics. Methodology. The hydrodynamics of groundwater is described by a two-dimensional equation (planar model) of filtration of a non-pressure groundwater flow. To model the process of aggressive impurity movement in the groundwater flow, a two-dimensional equation of convective-dispersive spreading of the pollutant in a non-pressure groundwater flow is used. Two finite-difference splitting schemes are used to numerically integrate the groundwater filtration equation. For the numerical integration of the equation of mass transfer of an aggressive impurity, a splitting scheme for physical processes is used. Finding. The software implementation of the developed numerical models of groundwater dynamics and mass transfer of aggressive impurities was carried out. The developed computer codes are a tool for operational analysis of the permeable barrier efficiency. Originality. The solution to the complex problem of geomigration - the movement of an aggressive impurity and its neutralization in a permeable barrier - is considered. To analyze the efficiency of the permeable barrier, a numerical model of groundwater dynamics and mass transfer of an aggressive impurity in groundwater was developed. On the basis of the developed numerical models, computer codes for computational experiments were developed. The developed numerical models make it possible to carry out a series of calculations within one working day to scientifically substantiate the parameters of the permeable barrier. Practical value. The developed numerical models make it possible to quickly solve complex problems in the field of water resources protection from pollution.

Numerical Models in Applied Problems of Heat and Mass Transfer

V. V. Biliaieva, S. A. Shcherbyna — Thu, 11 Dec 2025 00:00:00 +0200

Purpose. The problems of farm ventilation, prediction of CO concentration fields inside farms, prediction of artificial soil heating in greenhouses are considered. To solve a complex of such problems, it is necessary to have specialized mathematical models, oriented towards users in design organizations. Development of numerical models for solving heat and mass transfer problems for agricultural facilities (farms, greenhouses). Methodology. To solve the problem of ventilation of the working room (determination of the air flow velocity field in the room), a mathematical model of the motion of a vortex-free flow of an inviscid fluid (Laplace equation for the velocity potential) is used. Numerical integration of the modeling equation is carried out using two schemes: a locally one-dimensional scheme and a conditional approximation scheme. The G. Marchuk model is used to model the mass transfer process. Splitting schemes are used for numerical integration of the modeling equation. Two numerical models are built to analyze thermal fields in a stationary environment: a two-dimensional energy equation and a one-dimensional energy equation. Two difference schemes are used for numerical integration of the two-dimensional energy equation: a conditional approximation scheme and an explicit finite-difference scheme. An implicit splitting scheme is used to solve the one-dimensional energy equation. Findings. The software implementation of the developed numerical models has been carried out. The results of computational experiments are presented. Originality. Effective mathematical models and computer codes have been developed for solving problems of aerodynamics and mass transfer in the working space, as well as the process of heat conduction in a stationary environment. The created numerical models belong to the class of "diagnostic models", that is, computer codes that implement the developed numerical models make it possible to quickly obtain estimated data on thermal or concentration fields in the study area. Practical value. The created computer codes can be used to analyze thermal and concentration fields in agricultural premises (greenhouses, farms) to analyze the efficiency of energy systems and ensure the necessary ventilation and heating modes of the environment.

Current Issues of Safety Measures in Railway Transport Logistics

V. V. Gudimov — Mon, 22 Dec 2025 00:00:00 +0200

Purpose. The purpose of the study is to conduct a substantive comparative analysis of the state of occupational injuries related to the official activities of military personnel during the transportation of military cargo by rail and to justify the prevention of accidents, fatal accidents involving military personnel, and accidents resulting in serious injuries to military personnel. Methodology. Problematic issues during the loading of military trains and transports in modern conditions are highlighted. Comprehensive measures aimed at optimizing and implementing safety measures during loading and unloading operations are identified. Based on the analysis, proposals are made for the organized loading (unloading) of trains and transport in compliance with safety measures. The study uses the practical experience of officers of the military transport service of the Logistics Command of the Armed Forces of Ukraine. Military units that are transported as part of military echelons and send military cargo to ensure the fulfillment of tasks to provide troops with everything they need for life and operations during wartime. Findings. During a special period, the transportation of military units by rail is one of the main methods of strategic and tactical movement of troops, weapons, equipment, and material resources, as well as the evacuation of the wounded, equipment, and supplies. Originality. Development of recommendations and reference and analytical material for military units, military command bodies, heads of military transport departments on railways, and military commandants. Systematization of the work of commanders (chiefs) to ensure and enforce the rules for providing first aid to victims, safety while on the tracks of railway stations, the use of fire extinguishing equipment, as well as signals used in railway transport by military echelon personnel and guards. Practical value. Ensuring the preservation of life and strengthening the health of military echelon personnel and guards during the protection and escort of military transports with dangerous cargo (ammunition) in areas of operations (combat actions).

Mathematical Modeling of Air Pollution After a Quarry Explosion: Express Forecast

Mon, 15 Dec 2025 00:00:00 +0200

Purpose. Development of a CFD model that makes it possible to quickly predict the level of dust pollution of atmospheric air after an explosion in a quarry, development of a fast CFD calculation model. Methodology. To solve the aerodynamics and mass transfer problem, the fundamental equations of continuum mechanics are used. The air flow velocity field is modeled using the Laplace equation for the velocity potential. Numerical integration of the Laplace equation is carried out using the splitting method. After splitting, difference equations are constructed that can be solved by an explicit formula. The G. Marchuk model is used to model the distribution of dust in atmospheric air. Difference splitting schemes are used for numerical integration of the mass transfer equation. At the first stage, physical splitting is carried out into the equations of diffusion and convective dust transport. Then, alternating triangular difference splitting schemes are constructed. The terrain is modeled on a rectangular difference grid using markers. Findings. A set of numerical models has been developed to solve the problems of aerodynamics and mass transfer of a significant impurity in atmospheric air. Finite-difference splitting schemes have been used to build numerical models, which allow obtaining simple calculation dependencies. The constructed numerical models make it possible to quickly calculate the dynamics of dust pollution in conditions of complex terrain. Originality. Numerical models have been built to analyze the dynamics of dust pollution of atmospheric air after an explosion in a quarry. The model makes it possible to take into account the geometric shape of the relief, weather conditions, the rate of gravitational dust deposition, atmospheric diffusion, and the shape of the dust cloud after the explosion. The model can be used for rapid assessment of the impact of explosions on the environment. Practical value. A specialized package of computer programs has been developed to conduct a computational experiment based on the constructed numerical models. The results of the numerical experiment are presented.

Environment Pollution Modeling on the Base of Quick Computing Models

T. I. Rusakova, O. V. Berlov, O. I. Gubin, O. Yu. Gunko, P. B. Mashykhina — Wed, 24 Dec 2025 00:00:00 +0200

Purpose. Development of a fast calculation models for determining zones of ground waters and air chemical pollution during the emission of chemically hazardous substances from anthropogenic sources of pollution. To model the process of passive impurity transfer in ground waters and in atmospheric air, the G. Marchuk model is used, which takes into account the speed and direction of the flow, the intensity of the emission of chemically hazardous substances, and atmospheric diffusion (dispersion in round waters). Methodology. The process of ground waters and air pollution modeling is based on the numerical integration of the mass transfer equation (G. Marchuk model). Two numerical models were built. One numerical model was built to simulate ground waters pollution. Another numerical model was built to simulate air pollution. The construction of a numerical models of the impurity propagation process was carried out by splitting of the mass transfer equation (G. Marchuk model). Then a variable-triangular finite-difference decomposition schemes were used for numerical integration. The unknown value of the concentration of a chemically hazardous substance is carried out using explicit formulas. A set of applied programs has been developed based on the constructed numerical models. Findings. A set of applied programs has been developed based on the constructed numerical models. The results of numerical calculations are presented, showing the efficiency of the proposed numerical models. Originality. Proposed numerical models of mass transfer allow to compute quickly the areas of chemical air pollution due to the emission of toxic substances from anthropogenic sources of pollution. Practical value. Based on the proposed numerical models, a computer code has been developed. The developed models and computer code make it possible to estimate the size and intensity of environmental pollution, and can be used in solving the problem of assessing the negative impact on the ground waters and air from different sources. The results of numerical calculations show the operability of the proposed models.

On the Need to Conduct Additional Stress Tests to Evaluate the Safety of the Hydraulic Structures Site at the Zaporizhzhia NPP

V. Yu. Ulyanov, V. V. Bilyk — Tue, 09 Dec 2025 00:00:00 +0200

Purpose. Conducting a comprehensive analysis concerning the condition of the cooling pond dam at the Zaporizhzhia Nuclear Power Plant (NPP), which is a key component in the hydraulic structures system at this NPP, to justify further research. Additionally, identifying any extra or previously unaccounted factors that could affect the overall safety of the structure. Methodology. The authors performed a comprehensive review of all available engineering surveys and geotechnical research materials related to the Zaporizhzhia NPP cooling pond dam. These materials were produced by various organizations starting from the completion of the facility in 1985, with particular focus on the period 2011–2018, especially after the publication of the 2011 stress test report. Special attention was given to high-precision geodetic data on settlements and deformations of grades on the cooling pond dam. This enabled a new perspective on the findings of the engineering and geological surveys, as well as the stress tests conducted based on them. Findings. Based on the analysis of the dam body soil research data, previously unaddressed issues were raised and examined, including those related to the facility's operation. The need to conduct new stress tests was justified, considering the current conditions at the NPP site and its surroundings. Practical value. For the first time, a comprehensive analysis of the facility's condition was conducted based on accumulated geotechnical data. The stress tests performed in 2011 were found to be overly optimistic. Originality. The need for further research on the facility was justified, including through a program to evaluate the technical condition of the cooling pond dam using innovative methods from the Prydniprovska State Academy of Civil Engineering and Architecture.

Increasing the Level of Safety and Security of Transport Infrastructure from Air Threats Based on Their Acoustic Identification

D. O. Bosyi, O. I. Sablin, I. Yu. Potapchuk — Wed, 24 Dec 2025 00:00:00 +0200

Purpose. The purpose of the study is to enhance the safety and protection of transport infrastructure through the development of an intelligent monitoring system capable of detecting and classifying aerial threats based on their acoustic characteristics. The work focuses on designing algorithms for the early recognition of unmanned aerial vehicles (UAVs) and cruise missiles near critical infrastructure, addressing the growing importance of autonomous safety systems under hybrid threat conditions. Methodology. The research applies a comprehensive approach combining digital signal processing, machine learning, and embedded computing. Acoustic signatures of aerial targets were analyzed in MatLab using Audio Toolbox and DSP System Toolbox. Mel-Frequency Cepstral Coefficients (MFCC) were used as primary features to capture the most informative frequency components. The artificial neural network model was optimized for STM32 microcontrollers and implemented using CMSIS-DSP and X–CUBE–AI libraries. Wireless data exchange between sensor nodes employed ZigBee and LoRa protocols, ensuring scalable and energy-efficient communication. Findings. The system provides real-time acquisition, processing, and classification of acoustic signals with an accuracy of 85–90%. The MEMS-based sensor node prototype performs fully local processing without cloud services. Originality. For the first time, a concept integrating acoustic identification of aerial threats into transport infrastructure monitoring has been developed using embedded artificial intelligence, on-device learning, and local decision-making capabilities. Practical value. The results can be used to create distributed early-warning systems, upgrade contact line and infrastructure monitoring, and strengthen technological autonomy in defense and transport security applications.

Modern methods and tools for working with time series

A. A. Zhadan, V. I. Shynkarenko — Thu, 25 Dec 2025 00:00:00 +0200

Purpose. To conduct a structured analysis and classification of modern methods and models used to work with time series of various nature. Attention was paid not only to typical features and types of calculations, but also to identifying the subject area of application, comparing and highlighting strengths and weaknesses when working with different data sets, with relevant examples of areas of use and an emphasis on advantages. Methodology. A step-by-step and detailed review of existing methods and models based on their main characteristics, areas of use, and features of working with approaches of different nature that use different properties of time series. Findings. Analysis of the most common methods for processing time series and a separate review of their representatives. Particular attention is paid to hybrid models that can combine methods of one or different classes, as well as atypical approaches based on the specific properties of time series, in particular their fractality. Originality. It consists in a comprehensive and fundamental consideration of methods for analyzing time series, ranging from classical linear and nonlinear statistical models and artificial intelligence methods to hybrid and fractal approaches, with an emphasis on identifying their areas of application and comparing their advantages and disadvantages. The practical value of the research lies in the systematization of material that can be used for preliminary analysis of the subject area and selection of tools based on their effectiveness, which, in turn, simplifies the search for analogues and reduces the time required to prepare for research. In addition, the work highlights lesser-known and atypical methods that are of interest for further research and may be promising candidates for future scientific developments in the field of time series analysis.

Improving the Traction Properties of the Shunting Diesel Locomotives ChME3 by Distributing the Traction Force Between the Axles of the Diesel Locomotive

Fri, 05 Dec 2025 00:00:00 +0200

Purpose. Research into the specific determination of the influence of redistribution of traction force between axles on increasing the traction properties of the ChME3 diesel locomotive. Methodology. A mathematical model has been developed to determine the coefficient of utilization of the coupling mass of the ChME3 diesel locomotive when redistributing the tractive effort between the axles of the diesel locomotive. It is shown that as a result of the action of forces in the gear meshing of traction reducers and the action of the traction force on the automatic coupling, the unloading of the first, second, and fourth axles and the loading of the third, fifth, and sixth axles occurs in the direction of movement of the locomotive. Finding. Calculations of the coefficient of utilization of the traction mass of a diesel locomotive were carried out at different values of the coefficient of coupling and different schemes of power supply of traction electric motors. It was determined that the highest values of the coefficient of utilization of the traction mass of a locomotive are achieved in the case of individual power supply and control of traction electric motors. This method of power supply allows for the most accurate consideration of the actual axle load when redistributing the tractive effort between the axles of the locomotive. With group power supply of traction motors, in the case of combining axles with close axle coupling mass utilization coefficients, almost full utilization of coupling mass is also achieved. At the same time, the value of the coefficient of utilization of the traction mass of the diesel locomotive is stable and practically does not depend on the traction force. With by-bogie power supply and group power supply of all electric motors, the coupling mass utilization coefficient varies in the range of 0.8…0.87, with lower values being achieved at higher traction force of the diesel locomotive. Originality. The possibility of increasing the traction properties of the ChME3 diesel locomotive by redistributing traction forces between the axles of the diesel locomotive, taking into account the redistribution of the actual axle load, is substantiated. Rational options for power supply schemes for traction electric motors have been identified, which ensure a high utilization factor of the traction mass of the diesel locomotive. Practical value. The results obtained can be used in the modernization of ChME3 diesel locomotives, which allows to increase their traction properties. The proposed approach to improving traction properties can be applied to other traction rolling stock.

Car Tunnels as a Climate Neutrality Factor for a Large City

H. I. Haiko, I. O. Savchenko, V. P. Tarasiuk, D. O. Bespalov — Tue, 16 Dec 2025 00:00:00 +0200

Purpose. Determining the development priorities for a network of car tunnels envisioned in the Kyiv city General Plan, considering the city’s climate neutrality problem; systemic evaluation of a car tunnel’s impact on the city’s functioning, traffic change, and ecological (climate) indicators. Methodology. Modified morphological analysis method for urbanized territories, considering the groups of structural and functional, and ecological (climate) factors and risks, including: air pollution (car exhaust fumes), route length, traffic jams, dynamic noise etc. The transport model for Kyiv was introduced as a combination of two components – the transport supply model (consisting of the city’s traffic system elements: road network, different public transport routes, stations etc.), and the transport demand model (which characterizes the purposes for the choice of modes and routes for movement, population mobility parameters etc.). The synthesis of these methodologies is considered by the authors as an important process of converting scientific methods into management decisions. Findings. A systemic decision support model was developed for evaluating priorities, and ranking (advisable queueing) of tunnel construction in Kyiv considering the climate neutrality factor; a comparative assessment was made, and the highest-ranking tunnel was determined (the track from Galytska square to the start of the Brovarskyi avenue). Testing the scenario that incorporates said tunnel into the transport model of Kyiv allowed to assess the overall expected traffic change, and demonstrated the capacity to reduce overall СО₂ exhaust by 4 % of the total city’s emission. Originality. The novel construction of a morphological model for evaluating a system of car tunnels considering their impact on key risk factors that allowed to assess alternative configurations (scenarios) taking into account different priorities (weights) of a certain risk, particularly those impacting СО₂emission; a quantitative correlation was revealed between the tunnel’s track, its impact on the city traffic, and reduction of СО₂exhaust. Practical value. The paper demonstrates the high impact of car tunnels on the reduction of greenhouse gas emission (as well as mitigating a number of transport, territorial and safety issues) on the example of Kyiv city, providing the basis of considering the development of the underground traffic infrastructure as a constituent of achieving climate neutrality and sustainable development in big cities. Grant support. The research was conducted within the Horizon Europe frame program, project «Ukraine towards Carbon Neutrality (U_CAN)», grant agreement 101148374, and financed by the European Union.

Substantiation of the Optimal Sequence of industrial Building Reconstruction in Revitalization Projects, Taking into Account Their Future Function

T. S. Kravchunovska, K. V. Balakin — Fri, 19 Dec 2025 00:00:00 +0200

Purpose. Development of a methodological approach to the revitalization of former transport infrastructure objects, taking into account their future function (functions) within the constraints of time and resources. Methodology. A systems approach to modelling the revitalization process in terms of substantiating the sequence of inclusion of non-functioning transport infrastructure objects in the project; a comprehensive approach to forming a set of determining factors of exogenous and endogenous nature. Findings. A methodological approach to the revitalization of former transport infrastructure objects has been improved, taking into account the preservation of the authenticity of buildings, the adaptive use of their space, the application of building information modelling technologies, artificial intelligence, the Internet of Things, selective dismantling of structures, and soil remediation to meet safety, comfort, inclusiveness, and energy efficiency requirements, ensuring the commissioning of objects with specified technical and economic characteristics within existing resource constraints. Originality. A systems approach has been applied to the organization of the revitalization processes of former transport infrastructure objects, which involves a step-by-step analysis of the sequence of transformation of buildings and structures, taking into account the determining factors influencing the choice of their future function; at the same time, the tasks of transforming urban development by rethinking the functions of existing buildings instead of constructing new objects correlate with the tasks of creating sustainable housing, economic growth, responsible production and consumption. Practical value. The task of transforming urban development by rethinking the functions of existing industrial buildings instead of constructing new objects correlates with the tasks of creating sustainable housing, economic growth, responsible production and consumption. The proposed approach to determining the optimal sequence for the reconstruction of unused transport infrastructure objects with a change in their functional purpose in revitalization projects allows priorities to be set taking into account the influence of a number of determining factors and provides state authorities, local self-government bodies and investors with tools for making effective decisions under time and resource constraints, taking into account technical, legal and financial aspects.

Principles of the Concept of Reverse Conversion to Substantiate the Use of Underground Metro Structures as Shelters

O. L. Tiutkin, D. O. Bannikov, I. S. Ostapenko, M. V. Hernych — Fri, 19 Dec 2025 00:00:00 +0200

Purpose. The authors set the goal of determining the principles of the concept of reverse conversion to substantiate the use of underground metro structures as shelters for critical infrastructure facilities. Methodology. The article analyzes and classifies already constructed shelters, as well as dual-purpose facilities offered on the construction market of Ukraine. The features of protective structures, their design parameters, advantages and disadvantages are determined. It is noted that the emergence of new ideas and even the formation of concepts covering adjacent areas dedicated to shelters is associated with the development of the underground space of large cities, that is, with an area that has already been developed earlier. It is proven that the Ukrainian experience in the use of protective structures provides the opportunity to create a new concept in which already known designs of underground civil structures can successfully perform the role of shelters. Findings. To substantiate the use of underground structures as shelters for critical infrastructure facilities, a new concept has been introduced, which has been called “reverse conversion”. Reverse conversion is the process of transferring exclusively civilian design and technological solutions to the military sphere, as well as to the area close to it, namely the area of construction of protective structures. It is substantiated that a single-vaulted shallow metro station, built of monolithic reinforced concrete, and a column shallow metro station, assembled from precast reinforced concrete, have high potential as shelters. It is proven that design and technological solutions for the construction of underground metro structures (shallow stations) are transferred to the area of construction of protective structures, and are not used as dual-purpose facilities. Originality. The article first presents the principles of the concept of reverse conversion, which provides an opportunity to expand the space of solutions for creating protective structures. Practical value lies in in the substantiation of shallow subway stations as shelters for critical infrastructure facilities.

Mathematical Modeling of the Pylon-Type Metro Station Design Based on Numerical Analysis

K. Ye. Fedorov, O. L. Tiutkin — Fri, 12 Dec 2025 00:00:00 +0200

Purpose. The authors set the goal of conducting mathematical modeling of the pylon-type metro station structure based on numerical analysis using the finite element method, as well as searching for components of the stress-strain state and determining the strength of the combined reinforcement, which is constructed based on the New Austrian tunneling method. Methodology. To achieve the task, a finite element model of a pylon-type metro station was developed in the professional calculation complex Structure CAD for Windows. The model fully reflects the properties of the combined (temporary and permanent) lining of a pylon-type metro station. Half of the pylon-type metro station was modeled; the model was given deformation characteristics taken from real engineering and geological studies. Also, a set of boundary conditions was applied to the model, which corresponds to the real deformation of the system, as well as the combination of loads. Findings. During the numerical analysis, representative information was obtained on the stress-strain state of the pylon-type metro station and it was found that the presence of passages, as well as sections of the passage transition into the pylon and vice versa, indicates their significant redistribution. A detailed analysis of the frame displacements proved that the deformation of the frame of the middle and side tunnels confirms the almost uniform movement of the station structure. The maximum values of stresses in the permanent frame of the pylon-type metro station were determined. The presence of a system of pylons, as well as passages, forms a non-uniform stress state, which, in combination with a uniform deformed state, represents a defining advantage of the station structure of this type. Originality of the results lies in the first obtained during mathematical modeling of the stress-strain state of the structure of a pylon-type station, which is being built in strong soils based on NATM. Practical value. It is characterized by the results of the analysis of the strength of the combined (temporary and permanent) lining of a deep-buried pylon-type station.

Statistical Analysis of the Development of Ukraine’s Construction Industry in 2020–2024 and Organizational-Technological Implications

I. D. Shoniia, S. M. Olkhovyk — Wed, 17 Dec 2025 00:00:00 +0200

Purpose. To provide a coherent and accessible assessment of changes in Ukraine’s construction sector during the crisis period; to show how these shifts affected output, demand structure, the labor market, and firms’ financial performance; and to derive practical guidance for organizing reconstruction. Methodology. The study combines general scientific approaches with transparent statistical procedures. Comparisons are conducted on a harmonized, fixed territorial basis, excluding temporarily occupied territories and areas of active hostilities. We employ fixed-base and chain indices to track dynamics, a structural analysis of shares by construction product type, and a decomposition of sub-sector contributions to changes in aggregate indicators. Sensitivity checks are performed for the choice of base period and weighting choices, complemented by logical cross-checks of totals. Findings. We identify a sequence of contraction, adaptation, and gradual recovery. Evidence shows a persistent shift in demand from residential building towards engineering infrastructure and industrial facilities. The role of small and micro enterprises in employment increases, while financial outcomes diverge notably across activity types and firm-size groups. The findings also underline reliance on public reconstruction programs and the importance of transparent management of schedules, costs, and logistics. Originality. We propose a concise yet rigorous analytical framework that separates organic recovery from statistical base effects and changes in coverage. The nature of structural shifts is clarified; quantitative estimates of sub-sector contributions are produced; and the use of a fixed territorial basis is justified for correct intertemporal comparison. Practical value. The results support the prioritization of critical-infrastructure projects, realistic planning of resources and supply chains, and the design of contracting models with strengthened control of risk and cost. The analysis further substantiates the deployment of building information modelling with time and cost dimensions, the use of modular and industrialized solutions, flexible subcontracting arrangements, and digital monitoring—measures that enhance project controllability and coordination among stakeholders in a volatile environment.

Features of Level Crossing Construction with the Use of Dual Gauge (1520/1435 мm) on the Ukrainian Railway Network

M. B. Kurhan, R. V. Ivanov — Sun, 14 Sep 2025 00:00:00 +0300

Purpose. The purpose of the study is to justify and develop technical solutions for the construction of railway level crossings on dual gauge tracks (1520/1435 mm), taking into account modern technologies and operational requirements within the Ukrainian railway network. The lack of unified and optimized solutions hinders the pace of dual gauge implementation on key network segments. To address this issue, an analysis was conducted of existing international and domestic regulatory documents related to the construction of level crossings on dual gauge tracks. Various technological solutions and materials for level crossing decks (rubber-cord, reinforced concrete, and combined types) were examined and compared, with an assessment of their operational and economic characteristics. Methodology. To select the most rational design option for level crossing decks, the study employed methods of systems analysis as well as the Analytic Hierarchy Process (AHP) to substantiate technical decisions. The methodology involves examining the specific features of constructing crossings on dual gauge track, selecting optimal materials and technologies capable of ensuring safety, reliability, and cost-effectiveness for the successful integration of the Ukrainian railway into the European rail system. Findings. A hierarchy of criteria was developed, followed by pairwise comparisons, calculation of weight coefficients, and a comprehensive evaluation of alternatives. The application of AHP made it possible to determine the priority of different crossing deck types based on criteria such as durability, cost, vibration resistance, noise absorption, and maintenance complexity. Recommendations were provided for the implementation of modern level crossing construction technologies on the Ukrainian railway network. Originality. For the first time in the context of Ukraine, a systematic analysis and efficiency assessment of modern level crossing deck types for dual gauge was conducted. This includes the application of the AHP method for multi-criteria decision-making. Practical value. The results of this research can be used by the technical and design departments of Ukrzaliznytsia in developing and implementing projects on sections with dual gauge tracks, by track component manufacturers to adapt their products to modern requirements, and by design organizations in substantiating the selection of technological solutions.