Portable Device for Rail Bending and Torsion measurement

A portable device for assessing rail bending and torsion as well as the relative wheel-rail position was designed and tested. The main requirement for this device is that its first eigenfrequency should be well above the first bending eigenfrequency of the rail in order not to dynamically amplify rail bending motions. Thus, a minimum target frequency of 100Hz is set. Another requirement is to design a device that could be easily mounted on different track sections in order to assess also the influence of vehicle type and speed. Thus, a portable device based on laser sensors was produced that does not require any operations on the rails (contactless sensors) and allows to place the sensors at a reasonable distance from both the rail and the passing by wheel. Tests were performed on a dedicated test track in Czech Republic both at low speed (20km/h on a 150m radius curve) and at medium speed (90km/h on a 600m radius curve) with two axle and four axle wagons. Installation was extremely easy and acquired signals were post-elaborated to assess rail vertical and lateral bending as well as torsion.