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When modelling the dynamics of a rail vehicle ride, one of the important input parameters is the profile geometry of the wheel and rail treads. Commonly available simulation programs have databases containing some standardized profiles, or allow the profile to be added to the database. However, complications arise when a specific profile is required in the simulation analysis. Its geometry must be entered in the form of coordinates of the knot points that can be used to render the curve and thus define the desired profile. Simulation programs, however, do not have the ability to efficiently generate these coordinates. Since this is a lengthy process, the author team has created a program to define this profiles, based on their common drawing documentation. This program allows to create even large amount of profiles needed for variable rail treads definitions of crossings and switch points by a smart way.

The article deals with one of the ways of profile geometry design of a railway wheel and rail. The base for the creation of a new profile is an interactive attitude based on the modification of „the original shape which is defined by section of a railway wheel profile“, with to each other connected and exactly defined arcs radii. It is possible to change them according to shape needs of the final geometrical characteristics. Problems of the railway wheel/rail contact represents a basic point of any analysis which is connected with the moment of a railway vehicle on a track, with safety, speed, with comfort of people and goods transport. It is connected with the construction of new railway vehicles, with the reconstruction the old ones, with the approval (refusal) of vehicles into operation, with their evaluation as well as with the evaluation of track quality and their maintenance. It has a direct influence on the position of rail transport in the frame of the whole transport system, on economics, ecology and so on.

The study deals with a shunting impact of 13-4085 wagon platform to a TK25 tank container. In order to define the loads acting on the container frame, 3D computer models of the 1СС size container is designed, both version – for liquid and dry material transport. The virtual model consider a longitudinal force from the wagon automatic coupling, vertical and horizontal forces from the wagon – containers interaction and also vertical forces of the container fittings. For checking adequacy of the created models, the container acceleration values was obtained in two scenarios. In the first case, when fittings are aligned relative to the fitting spots of a wagon, thus without possibility of relative movement. In the second case, movement within clearance of fitting spots is possible. Mathematical models of dynamic loads on these structures were solved by MathCad. Differential equations were solved by the Runge – Kutta method. Adequacy of the created models was checked with an F-test. On the basis of conducted calculation can be conclude that the hypothesis on the adequacy of the models was not rejected.

In the article the results of studies of loading of the bearing structure of a wagon-platform of an articulated type, created on the basis of the existing construction, during transportation on the railway ferry by sea are given. In order to ensure the reliability of the fixing of the bearing structure of the wagon-platform of the articulated type relative to the deck of the railway ferry, it is proposed to equip it with knots for fixing the chain ties. To study the dynamic loading of a wagon-platform of an articulated type during transportation on a railway ferry by sea, constructed a mathematical model of oscillations with angular displacements relative to the longitudinal axis of the vessel (loll/heel). The maximal values of accelerations, as components of dynamic load, acting on the bearing structure of a wagon-platform are determined. The obtained acceleration values are taken into account when calculating the strength of the bearing structure using the finite element method implemented in the CosmosWorks software environment. It is established that the maximum equivalent tension do not exceed permissible values. The carried out researches will promote increase of efficiency of combined transportations in the direction of the international transport corridors.

The geometric relation between a wheelset and a rail is assessed with the help of geometric characteristics. Geometric characteristics are: equivalent conicity function, delta r function placement of contact points of a wheelset and a rail, tangent gamma function and effective conicity. It turned out that these characteristics are at present the most important not only for the judgment of ride characteristics of a vehicle on the rail but also for the wearing of wheel treads and rail heads, e. i., for the assessment of the track and vehicles in order to find out the current state and for the assessment of changes of the wheels and rails profile shapes in order to improve the current state too. The process of geometric characteristic assessment of a wheelset and rail with regard to wheelset rolling, as well as contact forces are analysed in the article.

The geometric relation between a wheelset and a rail is assessed with the help of geometric characteristics. Geometric characteristics are: equivalent conicity function, delta r function placement of contact points of a wheelset and a rail, tangent gamma function and effective conicity. It turned out that these characteristics are at present the most important not only for the judgment of ride characteristics of a vehicle on the rail but also for the wearing of wheel treads and rail heads, i.e., for the assessment of the track and vehicles in order to find out the current state and for the assessment of changes of the wheels and rails profile shapes in order to improve the current state too. The process of geometric characteristic assessment of a wheelset and rail with regard to angle of attack, as well as contact forces are analysed in the article.

In urban railway environments, the problem of tramcars passing small radius arches appears to be topical. In this regard, the authors proposed that the wheelsets should be complemented on the outer side of the wheels with a second tread of a lower radius, intended exclusively for ride in arches of the track with a radius which the conventional wheelsets cannot even theoretically pass without creep. The complemented wheel tread enters into operation (or out of action) as a result of passing over a specially shaped rail located in the intersections before and behind the small radius arc. In this process, there is a change in the wheel-rail contact location similar to what is commonly used when riding on a facing rail located in the immediate vicinity of the point frog. The paper deals with the comparison of these two cases based on a simulation analysis of vehicle ride. It can be evaluated, that changing the contact point when entering the arc by means of the proposed rails takes place in a more favourable way. It is possible to assume nearly 4 times longer service life of the proposed shaped rail than the one of a frog point.

The peculiarities of organization and perspectives of mass passenger transportation in the city and beyond are considered with the use of "Bus Rapid Transport" (BRT) or Metrobus. Different aspects of study of motor vehicles (MV) controllability and stability are analyzed. It is substantiated that it is sufficient to consider the potential stability of the MV itself, in order to guarantee the stability of the "driver MV" system with a large reserve. A mathematical model of a three-axle bus train consisting of a bus and two trains (metrobus) is developed and the factors influencing the critical speed as the main index of the stability of its movement are determined. It is established that the increase of the critical speed of the metrobus can be achieved by increasing the base of the bus, the first and the second trailer, as well as the mass of the bus and the coefficients of resistance of the drive wheels of the bus driving axle and the trailers axles. At the same time, increasing the distance from the mass center to the bus rear axle, increasing the distance from the mass center to the point of the coupling of the bus with the first trailer, increasing the mass of trailers and the resistance of the resistance of the wheel drive of the bus axis lead to a decrease in the critical speed of the metrobus. This must be taken into account both when designing metrobuses, and when operating them.

This research investigates the stability of a two-wheeled vehicle model on the basis of numerical determination of full range of eigenvalues of a linear approximation matrix in the vicinity of the rectilinear driving mode. The received result was checked by numerical integration of the initial equations system of the disturbed motion of the model. The discrepancy of two research techniques is explained by the specialty of the considered mathematical model in which two pairs of complex conjugate eigenvalues close to each other are realized, that explains the emergence of standard derivations at calculating their numerical determination. The model is asymptotically stable in the range much wider than an operational interval (up to 100 m/s). In order to provide more intensive dampening of initial disturbances, it is possible to introduce additional resilient and damping elements between the trucks and the body in the design of the wheeled vehicle that will counteract the yaw mode of trucks.

Tramways in cities often ride in track curves of a small radius, which is followed by an increased effect of the vehicle on the track. In the rail - wheel contact often occurs creep in longitudinal as well as in lateral direction, which causes increase of riding resistance, wear in rail – wheel contact and noise operation. Exactly with the aim to reduce these undesirable effects we designed a tram bogie with steered wheelsets and with the double wheel tread. This inventions are registered by authors under Utility Model Nr. u201609015 and Patent Application Nr. a201701589. Description of proposed process of passing vehicle through strongly curved track is given in this paper. A comparison of creep velocities in rail - wheel contact results obtained by computer multibody simulations for a tram vehicle riding through a S-curve are presented. Purposefulness of proposed invention is investigated by constructing vehicle ride resistance dependence to the track curve radius.

The article presents the results of determining the equivalent conicity characterizing the geometric interaction of wheels and rails on 1520 mm track. The cases of interactions of rails and wheelsets, wheels of which have different profiles, are considered. The computer model of the motion speed of the passenger car is developed. According to the results of computer simulation, critical speeds for the bogie moving through the tracks of indented gauge are received. Based on the results of the simulation analysis, the significant dependence of the value of the equivalent conicity on the critical speed is confirmed. The necessity of considering the limit values of equivalent conicity in tests of high-speed rolling stock is emphasized.

The mathematical modelling of the dynamic loading of the container-tank during maneuvering collision of the flat wagon has made it possible to obtain an accurate value of the accelerations acting on its supporting structure. At the same time, possible movements of the tank-container relative to the frame of the flat wagons due to the presence of a technological gap in the pair “fitting stop-fitting” are taken into account. It is established that this acceleration, which is a component of the dynamic load, exceeds the one permitted by the regulatory documents. A computer simulation of the dynamic loading of the tank container in the CosmosWorks software environment was also carried out. The calculation was carried out using the finite element method. The results of the simulation made it possible to determine the distribution fields of the accelerations acting on the supporting structure of the tank-container during the shunting of the flat wagon, as well as their numerical values. Checking the adequacy of the mathematical and computer models using the Fisher criterion allowed us to conclude that the hypothesis of adequacy is not rejected.

This paper describes the problem of rising temperature of the friction elements during braking. Negative influence of brake pads heating on the vehicle efficiency and traffic safety is well known. Methods of temperature stabilization in the contact of tribological elements during braking are proposed. Variants of brake pad application with additional elements consisting of phase transition material are considered. Their effectiveness is estimated. The effect of the contact characteristics on noise generation is analysed. The method of noise reduction is considered. The target function for the tribological processes management in the contact of the brake elements has been developed. The application of this target function allows using the braking reserve with the achievement of maximum braking effect with minimal wear and noise.

The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.

The dynamic loading of the bearing structure of the flat wagon from round pipes was investigated during transportation on the railway ferry. The main types of movements of the railway ferry with wagons located on its decks are taken into account. The research has been carried out on the strength of the bearing structure of the flat wagon by the finite element method. The coefficient of the reserve for the fatigue strength of the bearing structure is calculated, taking into account the action of cyclic loads in the conditions of sea disturbance.

The article is devoted to the analysis of the dynamic characteristics of the mechanical system composed of rigid bodies mutually connected with flexible bindings that represent springs and dampers. The analysed system represents the rail vehicle, which is distinguished by the contact link between the wheel and rail, or wheelsets and the track. Currently, analyses of similar type are carried out basically by using commercially distributed software packages, where you enter inputs (which the input forms allow) and the user may achieve results respecting the handling procedures. In accordance with the different approaches to solutions of partial solutions of the issue, the results of the simulations can differ. In the article the theoretical analysis is conducted the parameters of calculation are set out and the results are compared with the results obtained from the calculation by SIMPACK.

For Tram cars, it is often necessary to operate in cities on strongly curved track, which is followed by an increased effect of the vehicle on the track. Especially, this increased effect occurs in spiral transition curves situated between direct and arc sections or between two arc sections of different radius. In such case, increased guiding forces, creep in the rail - wheel contact, wear and noise generation can be observed. Exactly with the aim to reduce these undesirable effects we designed a tram bogie with steered wheelsets. This paper deals with a modification of its coupling to vehicle body in order to improve vehicle dynamics in transition curves. Proposed innovative construction of this coupling unit is registered by authors under Utility Model Nr. u201609015 and Utility Model Nr. u201703246. Description of the proposed way for a vehicle to pass through curved track with regard to bogie-body coupling and wheelset steering mechanisms with usage of multibody computing software is given in this paper.

The paper discusses the preconditions of the methodology development of diagnosis system for assessing dynamic impact of the rolling stock on the basis of processing and analysis of data obtained in operation on the results of measurement of parameters that characterize dynamic vibration processes of the mechanical system of “rolling stock – track”. On the basis of usage of the processing methods of time series and stochastic processes there has been established the relationship between these dynamic processes and wheel defects, and designed experimental data processing algorithms, which in the future will be an integral part of the intellectual systems of decision making when assessing the impact level of the rolling stock on the track. The article presents some results of the experimental and theoretical research of the rail accelerations data, which have been registered during passing of the train. The computational algorithm of the specialized pre-processing of the multidimensional signal recorded by this system is described. The advantage of this algorithm is that it does not require additional information about the train speed on the section equipped with the monitoring system, about the number of wheel pairs of locomotives and train cars, and about the distances between the wheel pairs. Based on the processing results of accelerations of the rails there have been set the parameters of increase in all statistical indicators with increase in the train speed. It is noted that the level of indicators for accelerations of the rails in the vertical direction is twice as high as the corresponding parameters in the horizontal direction.