The article studied the safety of passing the rolling stock by railway switches. On railway switches, counter rails provide the safe passage of the rolling stock by the wheelsets through the harmful space of the cross. The levels of dynamic effects arising from the passage of carriages by the railway switch significantly depend on the relative position of the wheelsets and elements of the switch, which is determined by the combination of their main geometric dimensions. To calculate the most unfavorable combinations of wheelset and gauge dimensions, taking into account the tolerances adopted for these dimensions, the method of probability compositions is used, based on the application of the theory of probability. The calculating apparatus of the approach using conditional probabilities of events based on the formulas of total probability and Bayes formula. The level of impact of the wheels on the counter-rail is regulated by rationing the values of the “impact effect” on the bent and catching parts of the counter-rail.

Abstract. This paper investigates the influence of wheel defects on the development of rail defects up to a state where rail prompt replacement becomes necessary taking into account different models of the dynamic contact between a wheel and a rail. In particular, the quasistatic Hertz model, the linear elastic model and the elastoplastic Aleksandrov-Kadomtsev model. Based on the model of the wheel-rail contact the maximum stresses are determined which take place in the rail in the presence of wheel defects (e.g. flat spot, weld-on deposit, etc.). In this paper, the solution of the inverse problem is presented, i.e., investigation of the influence of the strength of a wheel impact upon rails on wheel defects as well as evaluation of the stresses emerging in rails. During the motion of a railway vehicle, the wheel pair position in relation to rails changes significantly, which causes various combinations of wheel-rail contact areas. Even provided the constant axial load, the normal stresses will substantially change due to the differences in the radii of curvature of contact surfaces of these areas, as well as movement velocities of railway vehicles.

The paper is devoted to the formation of a system of reliability indicators for joints and rail crossings. Reliability indices related to the groups: reliability, durability, maintainability, safety, are considered. Since the joints and crossings of rail tracks consist of a system of elements, a model of functioning, in particular turnout, is built for their analysis. As a comprehensive indicator of reliability, it is advisable to use the availability factor - the probability that the object will be in working condition at an arbitrary time moment, except for periods of scheduled maintenance, and will work without fail during the periods between scheduled maintenance works. The basis of the methodology for determining the readiness coefficient of the turnout economy of an infrastructure object can be the concept of a reference turnout. As a reference turnout, it is advisable to take the most widespread type of turnout products used on the railroads of a particular infrastructure owner. Reliability indices of specific types of turnout products operated at specific places of track development of stations can be determined using a system of coefficients that take into account the design features of this turnout and the conditions of its operation. The greater the availability factor, the more reliable the transportation process is.