Vertical Interaction between Train and Track with Soft and Stiff Railpads—Full-Scale Experiments and Theory

Abstract

The vertical dynamic interaction between a running freight wagon and a tangent railway track has been investigated experimentally and numerically. Standard solid wheels without and with wheelflats were instrumented for measurement of transient vertical wheel/rail contact forces. Accelerations and strains in the track structure were measured in parallel. The location of the instrumented wheelset in relation to the instrumented portion of the track was determined at each instant of time. A portion of the track was equipped with railpads considerably stiffer than the soft ones used as standard in Sweden. The influence of train speed and axle load on dynamic responses was studied and compared for the two test sites. Track parameters determined at the test site were used as inputs to a mathematical model. Numerical results show reasonable agreement with measured responses. In the presence of wheelflats, measured dynamic contact forces were largely affected by pad stiffness and axle load. For some of the loading cases investigated, it was observed that soft pads did not always lead to lower contact forces. Maximum dynamic responses generally increased with increasing train speed.