Assessment of Train Running Safety, Ride Comfort and Track Serviceability at Transition between Floating Slab Track and Conventional Concrete Track

Abstract

It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.

A semi-analytical model of the train-floating slab track–tunnel–soil system considering the non-linear wheel/rail contact

“…21 built a 3D vehicle and floating slab model to investigate the running safety and ride comfort of the FST system. Li and Wu 22 and Jang and Yang 23 developed a 2D vehicle and FST coupled models to study the dynamic response of the system due to the transition zone between the FST and the conventional track. It should be noted that the main purpose of the FST system is to reduce the vibration transmitted from the vehicle and track structures to the foundation and soil, which are neglected in the models listed above, and this assumption means that these models lack explicitness in evaluating the vibration reduction effect of the FST system.…”

Study of the measurement and stability estimation of concrete roadbed slab at high-speed train in bridgeearthwork transition zone

“…The formula using track support rigidity at bridgeearthwork transition zone was shown through equation (1) and (2). These equations were based on continuous welded rail over support of longitudinal truss rigidity in longitudinal direction.…”

“…Especially the railroad structure connection with concrete bed at the bridge-earthwork transition zone is one of the parts, which is most complicated structure in the railroad infrastructure. It is also vulnerable section which may be easily occurred during roadbed settlement and deformation of railroad structure by differential settlement in railroad structures at transition zone according to sudden change of support rigidity [1]and [2]. Therefore, in this research, the behavior of the concrete roadbed slab in bridge-earthwork transition zone was induced by theory and compared with real behavior (value by monitoring system) and criteria of management reference to evaluate track support rigidity and driving stability of train [3] and [4].…”

Static and Dynamic Behavior at Low-Frequency Range of Floating Slab Track Discretely Supported by Rubber Mounts in Real-Scale Laboratory Test

“…플로팅 슬래브 궤도를 1-자유도의 질량-스프링 시스템 (mass-spring system)으로 단순화하면 스프링 상부에 놓이는 질량의 크기가 커질수록 스프링의 강성이 낮을수록 고유 진 동수가 작아지므로 진동 저감의 효과가 커지게 된다 [9]. 즉 진동 저감 효율을 높이기 위해서는 스프링 강성을 가능한 낮 추어야 하지만 스프링 강성이 낮아지면 궤도의 처짐이 증가 하여 시스템의 안정성이 저하될 수 있으므로 열차의 주행안 전과 승차감, 궤도 사용성 측면에서 상세한 검토가 필요하 다 [10]. 또 일반적으로 플로팅 슬래브 궤도의 설계는 1-자유 도 또는 2-자유도의 질량-스프링 시스템으로 단순화하여 시 스템의 튜닝주파수(1차 고유진동수)를 정하는 수준에서 이 루어지지만( Fig.…”