There are a large number of bridges, grade crossings, and rigid culverts involved in railway transportation, which result in plenty of track transitions. When high-speed trains pass through regions with abrupt changes in vertical stiffness, significant additional wheel–rail contact forces are generated. In this chapter, a dynamic analysis model of the train–ballasted track–subgrade coupled system is developed based on the vehicle-element and track-element modeling algorithms. To address the recurring issue of track faults caused by train-induced impacts at roadbed–bridge transitions in high-speed railways, parameter studies are conducted to examine the effects of train speed, track foundation stiffness, and transition irregularity on the dynamic responses of both the vehicle and the track structure in transition zones.