Abstract: Substantial frost heave is observed in coarse fills in high-speed railway embankment. These coarse fills have very low water content and are located above the groundwater. In an attempt to explain the unexpected frost heave, it is proposed that the cyclic train loads cause the development of the excess pore water pressure in the underlying subgrade soils and hence #x02018;pump#x02019; up the water to the frost front, which in turn feeds the formation of ice and results in continuous frost heave. A simple quantitative model is developed to simulate the pumping-enhanced frost heave. The numerical results show that the proposed mechanism can indeed provide a legitimate explanation for the otherwise unexpected frost heave. The engineering implications of this new frost heave mechanism are also discussed, in the context of designing frost heave mitigation measures in seasonally frozen regions.