In recent years, global climate change has had a pronounced impact, leading to a surge in extreme weather events that have significantly disrupted the operation and utilization of transportation infrastructure. The current global warming trend has further exacerbated the thawing of permafrost in specific regions, resulting in a decline in the stability of high-speed railway embankments in permafrost areas under repetitive train loading, consequently compromising the safety of train operations. This study utilizes the COMSOL finite element software to conduct a rigorous hydro-thermal analysis of embankments. The analysis takes into account the influence of moisture-temperature variations on soil modulus, providing a comprehensive understanding of the dynamic response characteristics and critical velocity changes of embankments under the combined effects of freeze–thaw cycles and train loading. The findings of this study serve as a robust theoretical basis for the construction, operation, and speed enhancement of high-speed railways in frozen soil areas, contributing to the advancement of infrastructure development in these challenging environments.