Dynamic Effect of Hollow-Worn Wheels for Freight Rail Vehicles in a Consist

The evaluation of long train dynamics involves different research topics such as optimization of numerical models with a large number of degrees of freedom, modelling of friction, constitutional laws of connecting elements, numeric simulation, among others. Besides those generic requisites, other particular details of typical applications of freight rail car modelling must be addressed such as wheels wear, misalignment of vehicle components, breakage of suspension system, asymmetry distribution of loads, uneven braking etc... Additional modelling difficulty is added when considering all the previous aspects associated also to dynamics simulations. This way, the goal of the work is to present a systematic to analyse the dynamic effects of worn and new wheels, on a convoy freight car and a freight rail car duo, using a multibody modelling software platform. Coupling longitudinal forces are calculated from an efficient draft gear model under a typical operational speed profile in a Brazilian railroad with curves and irregularities. The risk of derailment and the wheel surface geometric alteration is evaluated, and also other operational parameters the freight rail car, that may be used to minimize vibration, noise and track maintenance. The work also shows comparative results of the derailment coefficient Y/Q and wear index on the conditions of new wheels and tread and flange with hollow defects.