Upgrading the railway infrastructure technical parameters using the example of the Control-Command and Signalling subsystem with the EC verification certificate

Abstract

Droppers connecting the contact wire and messenger wire of the railway catenary are characterized by zero or negligible compressive stiff ness, hence they become slack under compression that is similar to bars' buckling. Th e paper presents a numerical analysis of the infl uence of droppers slackening phenomenon on the dynamic interaction between the pantograph and catenary. Th e analysis is based on a simulation method presented by the authors in previous papers, in which the catenary is modelled as a complex cable system. In this paper, the simulation method is modifi ed by introducing the residual compressive stiff ness of droppers that is assumed as a given percent of tensile stiff ness. Modifi cation leads to geometrically non-linear equations of motion of the pantograph-catenary system. Two diff erent algorithms for solving the problem of non-linearity are proposed, in both of them the Newmark numerical integration method is applied. Results of dynamic response simulations performed for diff erent values of residual compressive stiff ness of droppers are presented and compared. It is shown that the contact wire does not cooperate with the messenger wire in a large area around the pantograph when the compressive stiffness of droppers is assumed zero. As a result, the pantograph moving at high speed induces severe vibrations of the catenary. It is also shown that droppers should be designed to have the residual compressive stiff ness equal to at least one percent of their tensile stiff ness. Th is is suffi cient to ensure an appropriate cooperation between messenger wire and contact wire, which is demonstrated by simulation results fulfi lling requirements given in the standard PN-EN 50318: 2002.