Dynamic Train-Track Interactions and Stress Distribution Patterns in Ballasted Track Layers

This paper focuses on developing train-track dynamic interaction models by consideration of ballast and subballast layers' stress distribution patterns. In this paper, the existing railway track pyramid models are more developed in the case of the stress distribution in ballast and subballast layers with and without overlapped stress areas. Based on the range of railway track specifications, three track pyramid models including stress overlapping initiation from ballast layer (Model 1), stress overlapping initiation from subballast layer (Model 2), and without stress overlap areas (Model 3) are established, and their equations of mass and stiffness are derived. In the next stage, the derived pyramid models are included in the numerical model of the train-track dynamic interaction. In this regard, the track model, including rail, sleeper, ballast, and subballast layers, and the train model, including car body, bogies, and wheels, are developed. Then, the developed model is validated by using a series of field tests. Finally, the effects of the pyramid models' parameters on the developed train-track dynamic interaction model are investigated.