Research on a short-sleeper type ballastless-track that can adapt to large foundation deformation

Abstract

Settlement and arch deformation on the ballastless-track foundation during rail transit operations pose challenges to the existing track structure, which can only accommodate up to 30 mm of foundation deformation through the replacement of fastener adjusting pads. These limitations result in prolonged remediation cycles, increased expenses, and disruptions to train runs. To address these issues, a height-adjustable short-sleeper ballastless-track structure is proposed. Using the vehicle-track coupled dynamics theory and FEM, this study investigates the geometric matching characteristics, modal behavior of the track structure and their impact on the dynamics performance of the vehicle and track system when the HSBS structure is adjusted to 200 mm. Findings demonstrate that the ballastless-track can easily adjust the height by modifying the thickness of pads or replacing the short sleepers, enabling effective adaptation to substantial track foundation deformation with an adjustment capacity exceeding 200 mm. Importantly, the vibration mode and natural frequency of the short sleeper remain unchanged before and after lifting the track structure. Under the condition of unchanged support stiffness, the stability of the track structure, as well as the safety and smooth performance of the vehicle, are maintained at the same level as before the height adjustment.