An analog simulation study of the rocking response of a railroad freight vehicle

The steady state response of a single large capacity railroad freight vehicle is presented. The vehicle is described through an appropriate multi-degree of freedom non-linear mathematical model. The equations of motion of the system are derived by using Lagrange's procedure. The analog computer is employed for solving the non-linear differential equations of motion for obtaining the system's rocking response in the time domain. The vehicle steady state frequency response is derived from a sequence of time responses. By utilizing the frequency response plots a complete study of the system sensitivity to variation in the suspension parameters is carried out. The study shows that a possible practical solution to the freight car rocking problem can be achieved by using additional stabilizing devices consisting of friction and viscous dampers.