Wheel-Rail Wear and Adhesion With and Without Sand for a North American Locomotive

Abstract

A systematic laboratory investigation, of the effect of sanding on wheel/rail wear and adhesion, is reported. The tests were conducted on the IIT-GMEMD Wheel Rail Simulation Facility, using Hertzian simulation of the conditions for a typical North American locomotive wheel. Experiments at adhesion coefficients of 0.24, 0.35 and 0.5, with and without sand application on a clean dry rail, show that ratios of terminal and average wear rates, for the two categories of tests, range approximately from 10 to 100. Archard wear coefficients for the two categories are in the range 10 × 10−5 to 50 × 10−5 for tests without sand and in the range 130 × 10−5 to 520 × 10−5 for tests with sand. The ratios of wear coefficients, for tests with and without sand, range from 5 to 30. Adhesion creepage characteristics of a locomotive wheel simulation under different contaminants, such as water, sand, diesel fuel, lubricating oil, sand after oil and oil after sand, are also reported. It was observed that the liquid contaminants decreased adhesion levels and increased creepage. Sand application reduces the high creepage due to liquid contaminants, simultaneously increasing the attainable adhesion levels. Contrary to earlier findings, it was observed that the degree of sanding does influence the adhesion creepage characteristics, low sanding rates resulting in higher adhesion levels and lower creepage as compared to medium/high sanding rates. The wear and adhesion studies indicate that the beneficial effects of sanding in improving adhesion are more than offset by the increased wear rates. This increase is one to two orders of magnitude, compared to no sanding condition, depending on levels of traction. It is concluded that application of sand should be avoided as far as possible and high adhesion should be achieved by other means in order to minimize wear and the resulting track and equipment costs.