Abstract. The article deals with detection of reduced stress in a braked railway wheel, based on thermal transient analysis on virtual models, which influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with detection of temperature fields which are a result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to a quarter model of the wheel to speed up the calculation. This analysis simulates two braking processes with subsequent cooling. Distribution of the equivalent stress was detected in the railway wheel cross section, at selected points. The input parameters were taken from the thermal transient analysis. These equivalent stresses result from thermal load.

When performing the technical tests of the brake system under laboratory conditions, it is necessary to create the same conditions as those in operation. The friction coefficient is dependent on a number of parameters, including airflow during ride and weather conditions. Therefore, during the take-over tests, both these conditions are obligatory to simulate. This paper describes the design of the chamber, which will allow the test stand RAILBCOT to carry out the so-called dry and wet tests with airflow as during real-life ride. It also isolates the acoustic emission and emission of braking material to the surrounding area when tested.

The paper deals with a study of actuator (brake cylinder) modification for generation of braking force in a brake unit. The original solution, carried out using the original brake cylinder in cooperation with the proportional pressure control valve, is sufficient in terms of correct function of the brake unit, but in terms of safety, the corresponding force sensor may be damaged in case of a control circuit proportional pressure valves defect. Another reason for the study is utilization of the total regulation range of the proportional pressure valve and improvement of the brake unit response time in case of braking force overload. Such overload results in tread or rotating rail surface damage. The article gives description of the currently implemented passive measures to increase safety against sensors damage, but also of proposed active measures to eliminate these defects by changing size and type of the brake cylinder.

The effort to increase the rail vehicle ride speed on existing tracks, or more precisely on modernized tracks with a lot of curves with a relatively smaller radius, lead to use of tilting mechanism of the vehicle body. The paper deals with simulation analysis of a rail vehicle with an active tilting system of the vehicle body, design of the rail vehicle in CAD program CATIA and dynamical analysis in program SIMPACK, with the RAIL expansion. Such body mounting on vehicle bogies is significantly more complicated than the design of conventional rail vehicles. The purpose of this type of body mounting is to increase the size of body tilt during ride in a curve and thus reduce the lateral unbalanced acceleration affecting the passengers, or allow higher driving speed in a curve with the same radius while keeping the lateral acceleration value respectively. Eight variants of different velocity, vehicle occupancy and setting of the tilting mechanism were analyzed. We determined the average value of passenger comfort NMV from the simulation results. We have determined the value of passenger comfort during the ride in a curve PCT from the simulation results.

Article deals with the detection of reduced stress in a braked railway wheel based on thermal transient analysis on virtual models, because they influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with the detection of temperature fields which are result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to the quarter model because of the acceleration calculation. This analysis simulates two braking with subsequent by cooling. Distribution of the equivalent stress was detected in the cross section railway wheel, at selected points. The input parameters were used from the thermal transient analysis. These equivalent stresses result due to thermal load.