The geological structure in western China is complex, and rigid catenary systems are commonly used for pantograph power supply in railway tunnel construction. Due to the space constraints within tunnels, the aerodynamic characteristics and fluid–structure interaction effects between pantographs and catenary systems directly affect train operational safety. Numerical simulation analysis of the pantograph–rigid catenary interaction in tunnels is revealed. In the pantograph, the connecting rod areas endure high pressure and are prone to fatigue damage, necessitating structural strength optimization. The rigid catenary exhibits laterally symmetric vibration with high torsional stiffness, meeting operational requirements. This study provides theoretical support for design improvements of pantograph–catenary systems in tunnel environments.