This study examines how inerter-based suspensions affect rail vehicle vibration. Configurations S1, S2, and S4 are sensitive to short wavelengths (~20 m), while S3 and S5 respond to long wavelengths (~105 m). Configuration S5 outperforms the others, effectively suppressing longwave irregularities and maintaining superior ride comfort. These validated findings provide crucial insights for optimizing high-speed-train suspension designs.