A new model and computer program have been developed to describe the propagation of non-stationary thermal fields in frozen soils with complex lithology for pile foundations of capital construction projects. The results obtained were used to predict changes in the dynamics of the bearing capacity of soil for the emergency support structure of a railway bridge in the permafrost zone. This support structure consists of 12 large-diameter piles, for which solar radiation is also considered for the piles located on the southern part of the support structure, which makes it possible to observe the effect of a thermal bridge, when during the summer season the accumulated heat spreads deeper and faster into the pile than through the ground due to higher thermal conductivity of the pile concrete. In the approach the prehistory of the thermal processes in the soil foundation is essential for the bearing capacity estimation. The results of numerical calculations are presented.