Experimental approach to assessment of safety against derailment of freight wagons

Abstract

For many years, methods for assessment the safety against derailment of railway vehicles have been developed and improved. Possible approaches to solve this task are conducting real in-situ measurements or the application of MBS simulations. The goal of both approaches is to reliably determine the lateral Y and vertical Q forces and their Y/Q ratio. The limit values of this ratio, which should not be exceeded, are defined by standards and in technical reports of the European Technical Committees. Based on the complex geometry of the wheel-rail contact and other parameters of the vehicle and the track, this should ensure that derailment will not occur. In the experimental approach or measurement of relevant parameters, in Europe there are several methods defined by the standard EN 14363. All of them are extremely complex and demanding in terms of conditions to be provided and logistics, so in recent times tendencies are to apply simulations. This paper presents the results of the derailment safety tests of several types of freight wagons using method 2 of EN 14363. The application of this method was made possible by the development of an original wayside system for measuring the wheel-rail contact forces and the development of a hydraulic test rig for twisting a complete wagon. The results of these tests show that some freight wagons, although with standard running gears and standard dimensions, have quite high ratio Y/Q forces during curve negotiation.