China railway, as the essential infrastructure of China national economy, has to face and solve a lot of technical problems so as to cope with the strategic requirement of continuous, rapid and healthy development of national economy. The main issue is to raise passenger train speed and develop high-speed train operation technology. It involves such fields as locomotive and cars, signaling and communication, traffic organization, railway construction etc., it is a huge and complicated system engineering. In the system, railway track, bridge and tunnel are the running foundation of rapid and high-speed train, their quality directly affect the train speed and running quality, such as running stability, comfort and safety. So it is necessary to study the influence of track irregularity on train running quality and take effective measure to control track irregularity during the development of high-speed passenger train operation technology, for ensuring train running safety, extending the service-life of track and vehicle parts and improving train running stability and comfort. In view of the above-mentioned facts, the influence on running safety and stability of quasi & high-speed passenger car under track irregularity excitation is the topic of the thesis. Taking vehicle-track or vehicle-track-bridge vertical and lateral coupling system dynamic model as analytical method, the thesis systematically discusses dynamic behavior of quasi & high-speed vehicles excited by track irregularities of the ballast track, the influence on dynamic response of rail/wheel system excited by rail surface vertical short-wave roughness, serviceability of running vehicles on bridge under excitation of special track irregularities caused by bridge arch, pier uneven settlement and subsidence error between abutment and subgrade. Track irregularities are actually complicated random processes, consisting of approximately stationary ergodic processes of general track irregularities in entire length and non-stationary processes reflecting geome
