Wear depth analysis for rail-car wheels: case of Addis Ababa Light Rail Transit Service

Abstract

Railway transportation is a superior mean of all modes of transport. Specifically, it has gained a crucial role in limiting traffic congestion in heavily crowded regions and in reducing polluting carbon emissions. In this perspective, rolling contact fatigue of railway components is the most crucial subject because it has an important role in determining the operational reliability of the wheel/rail system. Because of wheel wear, wheel re-profiling is usually required for proper wheel-rail interaction. However, wheel re-profiling reduces the wheel radius and increase flange thickness. Therefore, the strain energy density in the wheel tread is expected to increase while the strain energy on the flange is expected to decrease in the reprofiled wheel. This effect would either increase or decrease the life of the wheel depending on reprofiling frequency is done. On the other hand, the maintenance costs are expected to increase as the re-profiling frequency increases. For quality service and improvement of the service life of the railway wheels, with reduction of the maintenance cost, a problem-solving research idea is formulated through comparing the expected wear depth and the current operational wear depth. Therefore, this study is focused on the influence of reprofiling on the wear depth of a railway wheel. The adopted method in this study is based on analyzing reprofiling data of worn-out non- re-profiled and reprofiled railway wheel. A case study is taken at Addis Ababa Light Rail Transit Service (AALRTS). The wheel profiles are generated through measurement before and- after profiling at AALRTS. In a single pair of models of a worn-out wheel and a reprofiled one, the results show that the re-profiling process affects the wear depth. It increases by 18 mm after 75028 km while the expected wear depth is1.43 mm for the same mileage.