Force transmission and height adjustment stability of the new height adjustable long pillow ballastless track

To address the settlement issue in high-speed railway foundations, the present study introduces a novel ballastless track system called NHABT (New height-adjustable ballastless track). This paper outlines the structural characteristics of the track and provides a detailed explanation of the methodology employed for height adjustment. To account for the unique properties of the NHABT structure, this study establishes finite element and vehicle-track coupling dynamics models. Firstly, under wheel load conditions, the study investigates the stress distribution of the NHABT structure and analyzes the influence of track bed length, thickness, and height adjustment on the force transfer characteristics of the NHABT structure. Secondly, the impact of height adjustment on the quality of vehicle operation and the stability of the NHABT structure is examined. The results indicate that adjusting the NHABT structure within a range of 20 to 200 mm is achievable by changing the side support pad or sleeper. The maximum stress occurs in the folded corner area on both sides of the sleeper groove. The force transfer characteristics of the NHABT structure are not affected by the length of the track bed, but its thickness significantly influences the stress in the folding corner area of the sleeper groove. The vehicle running quality and the stability of the NHABT structure after the adjustment are maintained at the same level as before the adjustment.