Decoupling of wheel-rail lateral contact forces from wayside measurements

Running safety and stability of railway vehicles are provided by respect of track geometry and by observance of the limits of wheel-rail contact forces. The ratio between lateral and vertical forces has an effect on the guiding forces provided by the rail, which prevent the wheel flange climbing and the derailment. This highlights the importance of the development of measurement methods of wheel-rail contact forces. In this paper, we present an experimental method to estimate the lateral contact force starting from the measurement of the strains on the rail foot surface. A suitable combination of the recorded strains allows to reproduce the same continuous signal of the applied lateral force, decoupling the effects of the vertical one. These studies, based on finite element simulations and laboratory tests, show how to find a constant ratio between the applied lateral load and the recorded strains on the rail foot surface.