Application of Friction Modifier to Railroad Tracks

点击翻译按钮获取中文摘要

This proposal involves two different, although related, collaborative projects between UBC and LB Foster Railroad Technologies Corporation. Both projects concern the application of friction modifier onto railroad tracks, to optimize the coefficient of friction between the wheel and the track. An optimal coefficient of friction is one that is sufficiently high to permit hill climbing and safe braking, but is lower than the metal-to -metal coefficient. The reduced coefficient of friction of a railroad track with friction modifier results in lower rates of track wear and noise production, and improved fuel economy, relative to an uncoated track.One process that is currently used to apply friction modifier to railroad tracks involves oozing a pool of viscous friction modifier liquid onto the tracks. As a train wheel passes over the pool, the liquid coats the wheel, and the liquid coating on the wheel is carried downstream by the motion of the train, coating the track farther downstream. The mechanics of this process are quite complex, as they involve the interplay between the free surface of the pool and the moving wheel. We have developed a good model for the process when the wheel is extremely wide (i.e., the flow is two-dimensional) and the liquid is Newtonian, and we now plan to expand both the theory and experiments to understand the three-dimensional problem with a non-Newtonian liquid.A second process under consideration is the use of an electrostatic powder sprayer to transfer friction modifier powder to the track from a moving train. There are at least two major hurdles that must be overcome to permit electrostatic powder spraying in this application: the electrostatic spray would be exposed to crosswinds whereas paint spraying is normally done in a spray booth, and friction modifier powder is either a semiconductor or a conductor, which is much more challenging to spray than the typical (insulating) paint powders. The goal here is to make electrostatic powder spraying practicable for track coating.