Optimization of the design of relay valves for rail vehicles braking systems in the context of train traffic safety

Abstract

The article presents the functions of the relay valve and its place in brake systems of rail vehicles. The relay valve were divided according to their type, the structure and principle of their operation were discussed, and examples of rail vehicles and modules in which relay valves are installed are presented. Because of their function in braking systems the relay valves should be characterized by high reliability and correct carrying out the tasks in the braking system of rail vehicles. The article describes selected structural factors affecting the operation of the relay valve and which are important for ensuring the safety of train traffic. Such factors are the lubricants used in the relay valves and the way of controlling it simultaneously with two signals with the function of an alternative that eliminates unreliable elements of the braking system. The analysis of the test results of the lubricant parameters and the testing of the relay valves on the test bench showed that the correctness of the relay valves depends essentially on the properties of the lubricant used, especially at low temperatures. On the basis of the tests carried out, a grease was selected that at low temperatures meets the criteria for correct and reliable operation of relay valves in rail vehicles. In terms of the control method, a comparison of two control signal delivery systems to the relay valve has been made, a new design solution is presented that ensures greater operational reliability and thus greater safety of the train traffic.