Air Resistance of Rolling Wagons on the Marshalling Hump

Abstract

The resistance to wagon movement on the marshalling yard from the air and wind is now considered to be additional to the main resistance arising from friction in the axles and from rolling friction. Influence of air resistance on rolling speed is evaluated and analysis of change of air resistance coefficient Сх from speed on the hill, speed of head or tailwind, angle of attack is given in this article. This considers the movement of single wagon trailers on the downhill section of the marshalling yard. Roll-off modelling is based on the analytical solution to the differential equation of the trailer. A wagon model of the train is used, treating each wagon as a material point with a mass equal to that of the wagon and concentrated at its centre of gravity. The resistance to the movement of wagons on a marshalling yard from the air environment and from wind power is shown to be a major rather than an additional resistance. The results and their analysis make it possible to refine the current methodology for determining the specific resistance of trailers to movement. Specific practical recommendations are given.