It is essential to reduce track maintenance costs and to extend the periodic replacements of continuous welded rails (CWRs) based on accumulated passing tonnage. In this study, we carried out fatigue tests on existing laid rails, and estimated the remaining service lives. At the same time, we developed a dynamic stress analysis model for welded joints with boltholes to calculate the stress under a range of track conditions. The model is composed of a beam model to calculate the dynamic wheel/rail contact forces and a solid model to estimate the stress field based on the forces. The remaining service lives of welded joints with boltholes were also estimated.