Наведені результати теоретичних та експериментальних досліджень впливу шорсткості поверхонь на трібологічні властивості контакту «колесорейка» в криволінійних ділянках колії метрополі тену. За результатами досліджень вста новлені значення раціональної шорсткос ті контактуючих поверхонь, що послугує передумовою створення технології пре вентивного шліфування рейок для упо вільнення їх зносу при русі в криволінійних ділянках колії метрополітену Ключові слова: контактні напружен ня, модельні зразки, раціональна шор сткість, «колесорейка», колія метро політену Даны результаты теоретических и экс периментальных исследований влияния шероховатости поверхностей на три бологические свойства контакта «колесо рельс» в криволинейных участках пути метрополитена. По результатам исследо ваний установлены значения рациональной шероховатости контактирующих повер хностей, что послужит предпосылкой со здания технологии превентивного шлифо вания рельсов для замедления их износа при движении в криволинейных участках пути метрополитена Ключевые слова: контактные напря жения, модельные образцы, рациональ ная шероховатость, «колесорельс», путь метрополитена UDC 625.143 : 625.4

Abstract. In order to determine the method of contact surface treatment and to define the rational surface roughness in the wheel/rail contact for the minimal growth rate of contact fatigue defects the program of experiments in operational conditions was developed. On the basis of the results and calculations the coefficients of regression equations, which describe dependencies of the wear rate on the parameters of the contact surface treatment in real operational conditions were obtained. Besides, the diagrams of dependencies of the friction coefficient on the roughness of railhead contact surface of the high rails with and without lubrication, when laid in curves of underground systems, were built. The experiments conducted in operational conditions of Kharkiv Metro revealed the influence of roughness of the railhead side surface of the high rails in curves on the contact fatigue defect development after preventive grinding and lubrication. According to the results of the experiments it was established that the rail preventive grinding with simultaneous lubrication led to slower contact fatigue defect development in rails of underground systems. The rational roughness of the railhead side surface of the high rails in curves after preventive grinding, which led to the minimal rate of defect development, was defined.

Further development of the roadway network in Ukraine will basically take place by modernization, which, in fact, conversion of the system « Road Conditions-Traffic Flow-Environment» from one state to another. Generally, it changes not only the spatial axle position of an existing road, but also the geometric and technological parameters of the road. Modern technological design and construction processes demand higher accuracy and reliability in determining the output spatial parameters measured with survey methods and techniques. Therefore, substantiated higher accuracies and improved survey techniques are tasks of primary importance. They must be solved on the basis of determination of rational error limits in survey works and their influence on the accuracy of building, transport operational and economical parameters of the project and actual engineering structures. The objective of the study is to demonstrate possibilities and efficiency in using various models of the system of ensuring the accuracy in survey works for roadway modernization and for solving other tasks on determination of geometric element parameters of complicated sections on existing roadways.

During the operation, the upper railway track structure constantly tends to age, which includes the increasing number of failures. This process is controlled by the track maintenance system, which provides for the current maintenance of the track in a certain railway section. As part of the current maintenance of the track, in particular, works are performed to eliminate defective elements of the upper railway track structure, which appeared during functioning of the track structure. The dependence of the operational cargo turnover on the amount of transported cargoes has been analyzed. It is directly related to the issues of organization of maintenance of the railway track structure taking into account the current track operation conditions. Regression analysis of the reported data allowed establishing a mathematical model of the dependence of the value of operational cargo turnover on the value of the transported cargo. The service life of rails (rail bars) in the track section has been established to be related to the indicator separate rail failure during the period of operation of the upper railway track structure by defects. The safety level of rails (rail bars) can be determined based on the value of this indicator.

The qualitative performance of the track facility in Ukraine depends upon the technical state of rail track structure, which is determined by correspondence of the characteristics to the current Regulations for laying and maintenance the track on railways of Ukraine. And the parameters indicating the rail track stability directly depend on the carrying capacity of the rail base and the stress-strain behavior. The rail base consists of elements of various physical and mechanical properties, with its own deformation behavior and stressed state under force loading. Therefore, the stress-strain behavior of the rail base must be evaluated with an appropriate mathematic model showing a flow of forces from one element to another. The rail track structure operates under the power loading from a train. This load considerably influences operation of the rail track structure and conditions the changes in the technical state in operation. In operation the technical state of the rail track structure is getting worse because the residual deformations accumulated in it, which lead to lower train traffic safety. Nowadays requirements for operational safety of the rail track structure are high, and the problem of evaluation of the stress-strain behavior of the rail base is of great importance.