Abstract
Service tests of railway vehicles are a very efficient and reliable method to obtain the data that may be used to estimate the life-cycle cost of the vehicle. The purpose of this study was to analyse the data obtained in the course of service tests and propose the method for calculation of life-cycle cost of railway vehicle related to wear of the friction elements. Wheel profile measurements provided the data necessary to observe and calculate wear of the wheels. The role of the visual inspection, documented by photographs was to compare the condition of the brake shoes and wheels with relevant regulations and guidelines in order to confirm their fitness for further service. Based on the measurements carried out in the course of service tests, wear of the friction pair in relation to mileage was calculated. Analysis of the damage and other undesirable phenomena lead to calculation of the corrected, reduced life-span of the brake shoes. It has been shown that the severity of the damage may depend on the brake shoe type. Exemplary calculations of predicted friction pair life-cycle cost for different types of brake shoes are presented. The method for calculation of life-cycle cost proposed in the study considers friction pair only and does not account for all processes which contribute to wheelset wear. The influence of the brake shoe type on the life-cycle cost related to the tread brake friction elements of the freight wagon was investigated. It has been shown that wheel wear is the key functional property of the brake shoe in terms of life-cycle cost of railway vehicle. Considering this property when choosing the friction material can result in long-term cost reduction.
KEYWORDS life-cycle cost, railway tread brake, wear, friction couple characterisation, service tests