Direction-dependent dynamic response of pantograph–catenary systems in high-speed railway turnout sections

This study investigates the dynamic interaction between the pantograph and catenary system in high-speed railway turnout zones, focusing on main-to-side and side-to-main transitions in a No.18 turnout. A coupled finite element and multibody dynamics model was developed to evaluate contact force and pantograph head vertical displacement. The results show pronounced directional asymmetry during turnout transitions. At high operating speeds, the peak contact force in the side-to-main transition is approximately 25% higher than that in the main-to-side transition because of differences in the initial contact geometry. The contact wire of the side line is also about 20 mm higher than that of the main line, causing the pantograph end horn to intrude into the contact path of the main line contact wire and generate an impact force of approximately 100 N. In addition, contact wire irregularities cause abrupt changes in effective contact geometry and excite high-frequency pantograph oscillations. These effects intensify with increasing speed, resulting in larger contact force fluctuations, higher peak values, and an increased risk of transient contact loss.