Effects of train bogie patterns on the mechanical performance of ballasted railway tracks with unsupported sleepers

The support condition of railway sleepers has a significant effect on the mechanical behavior of railway tracks due to the passing of different trains. One of the important issues in this regard relates to existing unsupported sleepers on the railway tracks. These sleepers cause changes in the dynamic responses of railway tracks under a moving train. In the literature, the effects of train bogie patterns on the behavior of tracks with and without unsupported sleepers have not been completely investigated till now. Therefore, the present study investigates this issue using numerical analyses. In this regard, first, a finite element model of a railway track is utilized, and the results are verified and validated against those of previous studies. Then, equations of three vehicle models are derived and their interactions with the track model are investigated. These models include vehicles without bogies and vehicles with two- and three-axle bogies. During the numerical analyses, the effects of the unsupported sleepers on the dynamic performance of the track are studied. Finally, based on the achieved numerical results, many regression equations are derived between the train axle loads with rail bending moments, sleeper displacements, and support forces for tracks