In the practice of monitoring the technical condition of rolling stock components and assemblies during operation and repair, timely determination of geometric deviations in critical bogie components, automatic coupling devices, and other assemblies is essential. This determination is accomplished using specialized templates and gauges. This article examines the possibility of replacing expensive metal templates with polymer templates, which are significantly less expensive to produce. The relevance of such a replacement is explained by the relatively large number of required measuring instruments of this type and the number of specialists who need to use these templates and gauges during the repair and maintenance of railway rolling stock. The need for a single worker to use a wide range of templates in the field necessitates the search for lighter, easier-to-use alternatives to heavy steel templates.

This article analyzes various templates for determining rolling stock component parameters and identifies those that can be replaced with lighter and less expensive ones. Some of these templates, which are relatively simple and lack moving parts, could be experimentally replaced with a polymer material produced using 3D printing. The paper presents data on the production of such templates from various polymeric materials, as well as the specifics of manufacturing templates from different polymeric materials. PETG-plastic proved to be the most suitable material for template production, for which the article provides optimal parameters and printing conditions. A year of use of these measuring instruments demonstrated that they are more convenient to use, and their metrological characteristics are similar to those of metal templates.

This paper addresses the optimization of fuel and lubricating materials (FSM) delivery routes to special rolling stock on railways using the Clarke-Wright algorithm. The relevance of the study is determined by the need to solve the problem of combining mobile service vehicles (fuel tankers) with service locations (fuel depots) while minimizing logistics costs.

Based on real data from the West Siberian Railway section, a shortest distance matrix between five stations along road networks was constructed. The classical Clarke-Wright Savings Algorithm was applied one of the most effective methods for solving vehicle routing problems with capacity constraints. The algorithm was implemented in Python with step-by-step visualization of the route merging process.

The Clarke-Wright method reduced the number of fuel tankers from five (individual delivery to each client) to two, with a total route length of 86,9 km. The savings in transport vehicles was 60 %, resulting in significant reductions in operating expenses for fleet maintenance, driver wages, and fuel consumption.

The scientific novelty of the work lies in applying the classical Clarke-Wright algorithm to the specific task of optimizing fuel supply to special rolling stock on railways with detailed step-by-step implementation and result analysis. The obtained results demonstrate the practical effectiveness of the method and its applicability to railway transport. The proposed approach can be extended to other network sections and modified to account for dynamic constraints (time windows, variable demand volumes).

This article justifies the need to use spectral indicators of vertical rail track irregularities as additional diagnostic features when assigning scheduled preventive track surfacing on lines with particularly heavy loads. An analysis of the current B criteria established by the Rules for Assigning Repairs has been performed.

The authors propose their own spectral indicators: short wave energy (ranges D0–D1 according to EN 13848 classification), system degradation index, and dominant wavelength. Model data generated by superposition of harmonics with a given energy distribution across ranges was used for verification. The full-scale profile was restored using fast Fourier transform and the inverse transfer function of the chordal system.

It is shown that the current criterion (the number of second-degree deviations over three spring months) is reactive in nature and does not consider the spatial structure of irregularities. Statistical analysis of 3,205 km of the Trans-Siberian Railway confirmed that only 25.6% of deviations are recorded in spring.

The proposed indicators made it possible to reliably differentiate between model scenarios: for the scenario with a predominance of short waves (ballast defects), the energy of short waves accounted for 77% of the total, with a dominant wavelength of 2.78 m; for the scenario with long waves (systemic deformations of the subgrade), it was 20% and 125 m, respectively. With a conditionally equal number of deviations (25 per km), the traditional approach assigns both sections, while spectral analysis recommends additional diagnostics for the scenario with systemic deformations, which avoids inefficient costs. The results can be used in railway track diagnosis and repair planning systems, especially in the context of reduced investment programs by Russian Railways.

The results obtained justify the need to include spectral analysis of vertical irregularities in the system of additional criteria when planning repairs. Further research is aimed at identifying critical short-wave energy growth rates for proactive repair scheduling.

The article discusses the issues of assessing the optimal service life of 1/11 switch rail crossings. The article evaluates the average proportions of the most common 1/11 switch type installed on different types of tracks at stations using the example of four track sections (PCh T, PCh B, PCh Kar, PCh Kam) located along the Trans-Siberian and Central Siberian railways. For example, the average share of switchings on main tracks is 48%, on receiving and sending tracks 17%, on access tracks 11%, etc.

The shares of the average annual demand for new and old-year crossings of switchings of the 1/11 brand, with the existing level of the standard service life of crossings in 80 million tons and the doubled service life of crossings in 160 million tons, have been determined. From the condition of resource-saving rational distribution of old-year cross-pieces of switch-gears, the limit levels of cross-pieces after the first service life are determined.

The actual dependencies of the decrease in the average share of cross-pieces of switch-gears on the increase in their service life are established, for the operational conditions of the I and II tracks of the Trans-Siberian and Central Siberian railways. The ratios of the average design life of new cross-pieces and the optimal level of the coefficient of reuse of new cross-pieces after the first service life Ks (the minimum level of the share of fitness), including taking into account the variation of the average level of the service life of old cross-pieces, have been determined.

According to the presented methodology for determining the optimal (standard) level of service life of switch elements, the levels of the estimated service life of new crossings have been determined to ensure a rational ratio of the average annual demand for new and old crossings. The optimal estimated level of service life of 1/11-type switch crossings, in order to maintain a rational level of their suitability while ensuring an optimal ratio of the area for laying new and old switch elements, is 200-220 million tons.

The article presents a mathematical model for the loss of stability in a continuous welded rail system, based on the analysis of the deformed shape of an equivalent beam that simulates the rail-sleeper grid. The deformed area of an equivalent infinitely long beam divided into a buckling region characterized by transverse displacements and adjacent regions where only compression occurs. The length of the regions is unknown and determined during the solution. The distinctive feature of the proposed model is to take into account the release of compressive forces after loss of stability, as well as the non-linearity of deformations, but with the preservation of the Bernoulli hypothesis. The law of changing the compressive force depends on the accepted law of changing the resistance of the environment in which the deformation occurs. Model has been improved to account for the nonlinearity of resistance to longitudinal and transverse cross-section displacements of the equivalent beam. Resistance functions are obtained by the approximation of experimental points using the least squares method, non-linear in case of transverse resistance approximation. The system of non-linear differential equations, which is closed by boundary conditions and transversality conditions, is solved by the finite difference method. The difference equations use central difference formulas, which require a minimum length of the template. The solution is made by a method of successive approximations, ensuring a sufficient number of grid nodes. The results of track stability parameters calculations are presented. Including the critical value of the heating temperature of the rails above the fixing temperature, at which a stable deformed shape can exist. The results of the solution according to the refined model are compared with the results of the model with constant resistance and with the results of the model without the release of the compressive force. Refinement of the model by taking into account non-linearities of various natures is important for assessing the pre-critical state of a continuous welded track.

The development of the Russian railway network and the improvement of transportation technology are closely related to the development of increasing transportation volumes by rail. In the first stage of transport development, the increase in transportation volumes was mainly achieved through the construction of new railway lines; in the next stage, after the saturation of Russia's most developed territories, it was achieved through increasing the average weight of freight trains. At the same time, the main technical means for the formation and disbanding of freight trains, and the processing of cars were carried out in large cities, which led to significant costs. At the current stage of rail transport development, it is necessary to evaluate the effectiveness of the third method – the development of existing main lines by laying additional main tracks. This involves double-track inserts on singletrack lines and, in some cases, the laying of third main tracks on double-track main lines.

The article proposes a method for assessing the operating conditions of single-track sections of railway lines based on simulation modeling using the 'Barrier-2' program, based on determining delays in the passage of train flows, including those caused by train crossings. Delay calculations for non-packet and packet schedules with various inter-line travel times and train intervals were performed. The results substantiate a method for accounting for train delays on single-track sections, which can be used for the feasibility study of laying additional main tracks during the development of existing railway sections.

Hydrocarbon gaseous compounds play important role in the modern economy of the early 21^st century. The global annual production of natural hydrocarbons amounts to an impressive 4.10¹² m³. They are used as energy carriers, raw materials for the production of organic and inorganic substances, materials, products, and in other areas. All types of transport are used for the transportation of hydrocarbon gases (in various physical states, such as compressed, liquefied, or dissolved). This work focuses on rail transport; loading of liquefied hydrocarbon gases in 2025 is estimated at 13.4 million tons. The main volume is carried by pipeline transport, but marine, river, road, and, to a lesser extent, air transport also play a significant role.

Low-molecular hydrocarbon compounds, including 24 nomenclature positions of individual compositions, have been classified by the UN ECOSOS Committee of Experts on the Transport of Dangerous Goods and in accordance with the Globally Harmonized System of Classification and Labelling of Chemicals as dangerous goods of Class 2 (gases) and subclass 2.1 (flammable gases). Alongside their useful consumer properties, combustibility, and high calorific value, hydrocarbon gases have the potential for explosion and explosive transformation under difficult-tocontrol conditions. The manifestation of this property during transport poses a significant hazard, which is reflected in the prohibition of shunting tank cars with such cargoes from hump yards. The prohibition of shunting significantly reduces the technical and economic performance of classification yards.

This work is a continuation of research conducted at the university from 2005 to 2010 under contracts with Russian Railways. At present, the problem has not lost its relevance and continues to attract the attention of industry specialists. This work is devoted to studying the characteristics of cargo, primarily identifying the patterns of explosion and combustion of hydrocarbon gases, and attempting to differentiate conditions ‘by degree of danger’. In a series of studies, we plan to examine the influence of factors such as structural, thermodynamic, kinetic, phenomenological, environmental, and economic on the course and outcome of reactions; to search for the least dangerous gases and the least hazardous conditions for preparing an experimental program, first numerical, then full-scale, for the unloading of tank cars from hump yards. It should be noted that there is also a prohibition on unloading empty tank cars that previously carried hydrocarbon gases from hump yards.

This article examines the design and construction of railway lines on degrading permafrost soils. Problems arising from the thawing of permafrost foundations of railway embankments lead to a loss of roadbed stability, defects, and track deformations.

The Far East remains one of the most significant and strategically important regions of the Russian Federation, boasting abundant natural resources, but their development requires infrastructure development. The Far East has become a key destination for major export and import flows along the Eastern Polygon of Russian Railways.

This article examines thermal modeling of the cross-section of a railway embankment in the Eastern Polygon of Russian Railways, including the development of measures to stabilize the degradation of the permafrost foundation soils. Thermal modeling allows one to assess the condition of the existing structure with and without measures to stabilize the permafrost boundary, as well as to predict the future behavior of permafrost. The purpose of this article is to substantiate a set of measures for the design and construction of railway lines to prevent deformation of the embankment bed on degrading permafrost soils under conditions of increasing freight traffic and global temperature rise. Problems arising from increased loads and thawing of permafrost soils at the foundations of railway embankments lead to a loss of roadbed stability, defects, and deformations in the track. Currently, stabilizing the temperature regime of thawing permafrost soils at the foundations of railway embankments is a pressing issue.

This paper examines options for stabilizing the temperature regime of permafrost soils at the embankment base of the Eastern Polygon of Russian Railways using numerical modeling. Thermal calculations allow us to assess the condition of the existing structure with and without measures to stabilize the permafrost boundary, as well as to predict the future behavior of permafrost.

The operation of railway roadbeds in permafrost regions is accompanied by degradation of the frozen foundation soils, development of thermal subsidence and frost heave deformations. Traditional seasonally operating cooling devices have a fundamental limitation a long time to reach the design mode, during which subsidence accumulates and frost heave deformations develop in water-saturated clayey foundation soils. This limitation is due to the dependence of the freezing rate on the heat transfer coefficient of the cooling device, thermophysical characteristics of the soil mass, and climatic conditions of the site.

A design method for combined thermal stabilization of the railway roadbed foundation of transport structures in the permafrost zone has been developed, covering the full cycle from analysis of initial geocryological data to justification of the parameters of the active and passive stages of cooling device operation. The algorithm represents a closed iterative procedure, at each stage of which the adopted design decisions are verified against regulatory requirements for frost heave deformations and long-term thermodynamic stability of the soil mass.

A method for calculating frost heave deformations during foundation thermal stabilization has been proposed, based on an empirical logarithmic dependence of the volumetric heave coefficient on the radial freezing rate and numerical modeling of the stress-strain state of the roadbed-foundation system.

A criterion for selecting the heat transfer coefficient of the passive stage has been introduced, defining the permissible range and ensuring long-term maintenance of the formed negative temperature zone without thawing and without development of frost heave deformations beyond the maximum allowable value, accounting for predicted climate warming.

An approach to determining the equivalent heat transfer coefficient of combined thermal stabilizers using liquid nitrogen, based on the Nusselt criterion, has been proposed, enabling the transfer of laboratory test results to full-scale objects with modified geometric parameters without conducting repeated experiments.

Verification of the proposed calculation method was performed at the ‘Seven Larches’ test site in the Yamalo-Nenets Autonomous Okrug. Comparison of the calculated vertical displacements with field geocryological monitoring data demonstrated their quantitative agreement, confirming the reliability of the proposed method for calculating frost heave deformations during thermal stabilization of clayey soils with cooling devices.

This paper investigates the multi-agent traveling salesman problem with a common depot and dynamic distribution of service points. Unlike traditional approaches that require preliminary clustering and rigid assignment of points to agents, the proposed method ensures adaptive formation of service zones directly during route construction. The distribution principle is based on minimizing the distance to the agent's initial position, which leads to the formation of spatially separated and compact clusters. Routing within the formed subsets is performed using a modified ant colony algorithm, in which the transition probability accounts for, in addition to pheromone trail intensity and heuristic information inversely proportional to distance, an additional correcting factor reflecting the candidate's proximity to the starting vertex. This architecture allows solving clustering and routing problems in a coordinated manner within a single optimization process, eliminating the need for a preliminary partitioning stage. To reduce computational complexity, multi-threaded processing of formed clusters is implemented, ensuring algorithm scalability as the number of agents increases. Results of computational experiments on standard test sets of various dimensions confirm the effectiveness of the proposed approach in terms of minimizing the total route length. It has been established that integrating the proximity factor to the initial position into the heuristic function contributes to the formation of more compact trajectories compared to the basic version of the ant colony algorithm. With comparable computational costs, the dynamic distribution scheme provides an improvement in the objective function by an average of 6% and also enhances the system's adaptability to dynamic changes in input parameters.

Implementation of road projects under state programs for highway development, road safety improvement, and transportation safety requires high-quality design of road structures, particularly subgrade and pavement layers. Under these conditions, demands increase for both design solutions and the reliability of initial data, especially regarding geotechnical conditions, which form the basis for the durability, safety, and economic efficiency of road structures amid rising construction costs.

To assess the impact of accounting for subgrade soil characteristics on road projects involving repair, major repair, and reconstruction, the following were analyzed: soil data obtained during geotechnical investigations; discrepancies between calculated and actual soil relative humidity (per Eq. 3.5 of GOST R 71404-2024); and road structures designed using both calculated and actual relative humidity values. The analysis revealed the distribution of subgrade soil types across Novosibirsk Region and identified key properties requiring special measures for soil replacement or reinforcement. Significant differences were found between calculated relative humidity values based on standard tables and those derived from actual field data in geotechnical reports.

Based on the study results, it is recommended that regional soil characteristics be classified as a critical risk factor directly affecting road project implementation. Therefore, it is advised to incorporate requirements for defining regional soil properties into technical specifications for road project development.

During the operation of railways in the cryolithozone, in particular the Baikal-Amur Mainline, so-called thawing bowls were formed under the existing earth bed from draining soils in areas of high-temperature frozen soils. The infiltration of atmospheric precipitation into the body of the earth's surface is a key factor in its formation. Quantification of this effect is very problematic due to the uncontrolled nature of filtration processes in the body of the earth bed within the framework of traditional thermophysical calculations. The issue of precipitation filtration is particularly pressing given that the modernization of the Baikal-Amur Mainline, aimed at increasing its capacity, envisions the construction of second tracks on a common subgrade, which is primarily made of drainable coarsegrained rocky soils, in accordance with current design standards.

In this article, a hypothesis is proposed and justified by numerical modeling to solve the problem of accounting for the warming effect of atmospheric precipitation on the soils of the foundation of the roadbed. Its essence lies in the introduction of the concept of infiltration thermal conductivity, which is taken into account when determining the total coefficient of thermal conductivity of the draining soils of the earth bed in a thawed state. This approach to the description of the thermophysical picture of the draining soils of the earth bed and its base allowed us to substantiate the technological scheme proposed in the work for the phased stabilization of the frozen soil boundary at the base of the embankment during the construction of the second tracks. The process flow diagram proposed in the article eliminates the impact of the warming effect of atmospheric precipitation on the soils of the subgrade foundation. A distinctive feature of the diagram is the staged installation of waterproofing in the upper portion of both the newly constructed and existing subgrade, facilitating the restoration of the frozen state of the soil beneath the operational track.

This article examines the prospects of using polymer composite materials (PCMs) for bridge deck reconstruction. Irkutsk city contains a number of bridges characterized by reduced load-carrying capacity and insufficient durability, resulting from damage to the waterproofing layers of the bridge deck and the consequent deterioration of the load-carrying elements. Bridges with steel-reinforced concrete superstructures serve as examples of such structures. Employing polymer composite materials in the rehabilitation of superstructures, specifically as load-bearing roadway components, enhances their load-carrying capacity; this approach eliminates the necessity of a separate waterproofing layer, thereby reducing both the initial cost of the deck and expenses for its maintenance and repairs. The results of the work can also be applied to other urban bridges, including new ones.

The article analyzes the key advantages of polymer composite materials, as well as the primary limitations on their application. It also provides data demonstrating the reduction in operating costs for the maintenance of bridges utilizing polymer composite materials compared to reinforced concrete. For instance, the payback period for 1 square meter of composite roadway slab is approximately 35 years, which is roughly equivalent to 1.5 standard periods of waterproofing major repairs.

Using the MIDAS Civil 2022 software package, a finite element model of the overpass superstructure with a composite roadway slab was developed. Calculations confirmed the feasibility of the integrated behavior of the composite slab and steel beams; the material of the slab and steel beams meets the requirements of regulatory standards.