Railway axles represent a typical example of interference fit structures that are vulnerable to fretting fatigue induced by rotational bending loads. This study investigated the influence of interference magnitude on the fretting wear and fatigue of scaled press-fitted railway axles. In this study, the fretting fatigue strength was tested at three interference magnitudes within the standard range, and the fretting wear and fretting cracks were analyzed. The results indicate a trend where the fretting fatigue strength initially rises and then declines with increasing interference magnitude. 3D finite element models, with and without considering the fretting wear, were developed to investigate the variation in contact parameters in the press-fitted region, and the Smith-Watson-Topper multiaxial fatigue model was employed to evaluate the fretting fatigue behavior. The results demonstrate that the competition between contact pressure and axial slip produces relatively slight fretting wear when the interference magnitude takes the middle value, thereby causing a minor stress concentration and ultimately leading to higher fretting fatigue strength.