While the seismic design of railway bridges and tunnels has been extensively studied, the role of railway sleepers in track-level earthquake resilience remains largely overlooked. This study investigates the dynamic behavior of two sleeper types—conventional B70 and a novel H-type—using 3D-printed miniature track segments tested under free–free conditions. Experimental modal analysis (EMA) was performed to evaluate resonance frequencies, damping ratios, and dynamic amplification (CMIF peak values) across different excitation methods. Results show that excitation over the rail or sleeper has minimal effect on resonance frequency but can influence damping estimation. The H-type sleeper exhibited over 40% higher resonance frequencies, over 40% greater damping, and at least 27% lower CMIF peaks compared to the B70-type. These improvements suggest reduced vulnerability to resonance and better energy dissipation under seismic loads. This study highlights the sleeper’s overlooked contribution to seismic performance and introduces a practical, scalable framework for evaluating sleeper-level dynamics. Incorporating modal performance criteria—such as minimum lateral resonance thresholds and periodic EMA checks—into design standards is recommended, particularly for ballasted tracks in seismic zones. The findings support the development of next-generation sleeper designs optimized for earthquake resilience.