Measurement of vertical wheel force on the rail

Abstract

The efficiency of the proposed method, which measures the wheel force by using strain gauges installed on the rail, is investigated. Five full-scale tests were conducted in the maintenance center of CZ LOKO, Česká Třebová, Czech Republic. Six strain gauges (three active, three dummy) in each rail were installed in the half Wheatstone bridge configuration so that the wheel force can be calculated by the measured strain. While one active strain gauge was placed in the middle of the bottom flange of rail, two of the active strain gauges were mounted symmetrically to each other on the edges of the bottom flange. The optimal places of the strain gauges were determined by finite element analysis. Besides, both force and lateral shift dependence of the presented method were investigated with an experimentally validated finite element model. Two parametric equations corresponding to the results of finite element method are proposed. Moreover, two more equations were derived by means of a conventional method, which is an experimental calibration method. These equations are used to predict the wheel vertical force regardless from any lateral effect. All the results obtained from the equations were matched quantitively well with the measured mass in the weighing device.