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Analysis of failures of axlebox units of bogies for freight cars in the network of JSC «Russian Railways» for the period from 2010 to 2012, disadvantages of this node known construction trucks of the car of model 18-100. Defined vertical, horizontal and longitudinal loads acting on the buchs site. Mathematical modeling of the dynamic loading roller bearing axle-box under radial load. The influence of dynamic loads and defects in a roller bearing axle-box site on a safety of movement of the carriage.

An approach to the evaluation the actual energy savings achieved when implementing service contracts energy, based on the development of mathematical models of power consumption, taking into account the impact of production and climatic factors. An example of the calculation of the ac-tual efficiency of introduction of energy-saving devices at the Sverdlovsk railway is presented

The development of railway transport is currently impossible to imagine without the use of mathematical models and algorithms. Consider the increase in speeds, reduction of travel time, while minimizing costs, is possible only with the qualitative and full use of the mathematical apparatus. The use of information technologies makes it possible to take an effective decision in the development of a project for the reconstruction of a railway line. The current state of the theory of railway transport is characterized by the presence of a developed system of mathematical models and algorithms for analyzing various features of railways. This opens up possibilities for building an approach to the problems of searching and optimizing design solutions on a mathematical basis, with the reduction to a minimum of costly and time-consuming physical modeling procedures. One of the main tasks that are set for the railway transport in the near future is to increase the speed of trains on existing railway lines with the use of computer technology (computer-aided design). The article deals with the problems of technical reconstruction of the railway plan to increase the speed of train movement. The urgency of the use of computer mathematical methods for the development of an optimal plan for increasing the speed of trains. A pair of mutually dual problems of optimal reconstruction of railway curves to increase the speed of trains with minimal capital investment is considered. As methods for solving the problems posed, the following methods were proposed: the method of steepest descent, a modified method of dynamic programming (the Cattell method), the method of indefinite Lagrange multipliers. The expediency of using each method to solve the problem is indicated. The considered methods allow to implement a number of computer-aided design procedures for the reconstruction of the railway plan.

The article describes three variants of the mathematical model of the sensitivity function of the magnetoinduction sensor for assessing the influence of various sensor parameters in the electromechanical system «wheel - rail - magnetoinduction sensor» for diagnosing the technical condition of the rolling surface of the rolling wheels of rolling stock in the process of its movement over the sensor. An example of an algorithm for identifying defects located on the surface of the wheel rolling circle is described. The proposed multi-vector mathematical model allows simulating various defects on the rolling surface of the wheel, developing and testing new algorithms for processing the output signal of the sensor on the basis of modern hardware and software. The implemented defect identification algorithm is based on the property of the centrally symmetric form of the sensitivity function of the magnetoinduction sensor and the allocation of a useful signal corresponding to a certain type of defect, based on the application of a mutual correlation function and the assessment of its maximum and minimum values in comparison with the specified thresholds and confidence intervals. The main requirement for the implementation of the model is the uniform movement of the train above the sensor along a straight section of the rail track. This article discusses only one of the possible digital signal processing algorithms, but the proposed model allows us to compare the efficiency of other possible algorithms identification of defects in the rolling surface of wheelsets. The developed model confirms the prospects of using magnetic induction sensors for identification of not only visible, but also hidden defects on the rolling surface of the wheel in the process of movement of the train.

The article discusses issues of simulation modeling of technological processes of repair of rolling stock components. A model of the technological process of repairing a trolley (mod. 18-100) of a gondola car in an ARENA environment is given.

Resistive heating of the pantograph head due to the flow of traction current through the conductive elements of the upper node, has an uneven distribution along the frame structure and depends on the location of the contact wire on the insert. The aim of the work is to develop a mathematical model for calculating power losses in the pantograph panhead, allowing to estimate its value, taking into account the zigzag of the contact wire during the movement of electric rolling stock. The subject of the study is the pantograph panhead. The paper gives an example of calculating the frame skid of a pantograph equipped with carbon strips. Experimental studies of the current distribution over the shunts of the panhead depending on the position of the contact wire were carried out in February 2021 in the laboratory "Designs of contact networks, power lines and current collection devices" using a complex for testing current collection devices. The calculation of the heating power of the panhead is determined by the Joule-Lenz law. The results of the calculation showed that the maximum heating power is observed when the contact wire is in the middle of the panhead, while the places of the greatest losses located along its edges are above the places where the shunts are attached. The model makes it possible to obtain a functional dependence of the heating value along the panhead. The obtained results of the skid heating power distribution make it possible to supplement the complex model of the thermal state of the pantograph developed at the Omsk State Transport University with the participation of the authors of the article. The versatility of the developed model makes it possible to investigate various zigzags of the contact wire and evaluate the effect on the distribution of traction current along the panhead, depending on the location of the shunts and their number.

Shotcrete lining is one of the most common types of temporary supports in tunnel construction. The influence of shotcrete lining on design calculations of permanent lining is difficult, because there is no method of designing at the present time. This leads to increasing in consumption of materials and labour of construction. The information about the influence of the basic mechanical properties of soils, geometrical size of construction per value of temporary shotcrete lining factor was obtained during research. These data formed the basis for futher development method of designing.

The article presents the results of research of a point magneto-induction sensor based on a mathematical model, which allows you to increase the reliability of automated systems for diagnosing technical condition rolling stock in the course of train movement by improvement the accuracy of the initial information, that is, the moments of fixation passing of wheelset axles over magneto-induction sensors. At the first stage of developing a stigmatic mathematical model the analytical dependence of the value of the magnetic flux in the magnetic core and the output EMF value on resistance of the air gap between the sensor and the wheel crest. At the second stage of development of the mathematical model found time dependence of the magnetic resistance of the air gap between the core of the magneto-induction sensor and the comb wheels of a railway car moving along a straight track at a constant speed. On the basis of application the developed stigmatic model allows evaluating the energy parameters of magneto-induction sensors depending on the properties of modern magnetic materials. The simulation results showed that the MMF value is constant the magnet determines the main parameters of magneto-induction sensors, so the use of modern magnets based on rare earth they allow to eliminate the traditional disadvantage of outdated types of magneto-induction sensors, that is, to reduce their size and weight. The application of the proposed stigmatic model expands the scope of possible solutions to extreme problems for selection and justification parameters of magneto-induction sensors, helps to improve the accuracy of systems for diagnosing the technical condition of the car fleet and traffic safety on railway transport.

The authors consider the question of the limits of applicability of the capacitor method for measuring the real part of the dielectric constant of printed circuit boards and telecommunications cabled rail transport using the example of FR-4 fiberglass laminate and the cable PK-75-4-12 in the frequency range from 10 Hz to 100 MHz. The measurements were carried out at a constant temperature and humidity of a known material. Comparison of the obtained values with the passport data on the material is carried out; a measurement procedure is developed with overlapping frequency ranges by changing the values of the measuring resistors from larger to smaller with increasing frequency of the input signal. It is shown that in the high-frequency region, the measurement accuracy is directly affected by the parasitic inductance of the capacitor sample under study, as well as the active resistance of the leads and plates and its increase due to the skin effect. The article also discusses the ways of accounting and calculating the parasitic elements of a capacitor. One of these ways is to study the characteristics of the elements of the sample at the first proper serial resonance of the capacitor under study.

In the article presents the network model of processes of planning and the accounting of transportations, and also processes of execution of documentation at freight dispatch in the intra republican message of the railroads of Uzbekistan by means of composite document management. Composite document management provides the movements of documents in paper and in electronic medium, and also their composite decisions. The special the automated system (AS) will support processes of electronic document management and to make the reporting in the automated mode. For mathematical modeling of process of document management in this work it is used methods of network planning and management. It is described characteristics of the offered technology of planning and the accounting of transportations, and also execution of carriage documents at freight dispatch in the intra republican. It is applied, the PERT method for calculation of accidental temporary characteristics of works. Temporary characteristics of events are determined by a method of a critical way. Tables with the sequence of works with the indication of optimistic, probabilistic and pessimistic assessment of duration of performance, and also with results of calculations for determination of average time and dispersion are made. The network schedule of works, in compliance of technology of document management by means of which terms of performance of work are evaluated, entering document management process is made. Durations of critical and noncritical ways are determined. The results received in article confirm efficiency of the offered technology of document management. Use of this technology providing filling of documents electronically and fixing with the digital signature (DS), it is expected to lower expenses of time of consignors and the railroad, to increase productivity of works and quality of the provided services, to create the centralized information base.