A study on measuring rail/wheel contact points of running railway vehicles (improvement of the measuring method for wheel load and lateral force by strain gauges on disk surface)

It is interesting and worth while to study on method of measuring rail/wheel contact point and contact force of running railway vehicles, since many things in real rail/wheel contact phenomenon are still unknown, In this paper, the Japanese conventional method of measuring vertical load and lateral force is introduced. The strain of the disk surface is used for measuring forces. A new method, which detects the contact point as well as vertical load and lateral force, is proposed also in this paper. Firstly, the surface strain on disk type wheel is analyzed by an FEM program, NASTRAN, under the condition that vertical, lateral or longitudinal force separately acts on various points along the wheel profile. By the calculated result, it shows the possibility of detecting the rail/wheel contact point by means of measuring lateral distribution of compress strain which changes according to the load position, i.e. rail/wheel contact point. Secondly, the idea above is verified by static load experiments using an actual disk type wheelset. The location of an area where lateral force affects little on surface strain is investigated, since the lateral distribution of strain should be measured in such an area to avoid the interference of bending by lateral force. And finally, theory for the measurement is modified for on-track testing and the best position and direction for strain gauges is proposed in accordance with the calculated and experimental results.