Click Here For Full Paper
ABSTRACT
Transition zones, i.e. where the track stiffness changes abruptly, have been usually associated with track geometry deterioration, frequent maintenance and poor ride quality. Dynamic load amplification and a high level of stress concentration are often proposed as the main sources of the aforementioned track problems in these zones. The performance of transition zones is complicated and depends on both the railway track and train characteristics, such as train speed and the level of track stiffness change. In the present paper, a coupled train-track three dimensional finite element model is applied to study the mechanics of railway track transitions. This model incorporates the multi-layered nature of the sub-structure, soil & ballast nonlinearity and the interaction between the track and train. Railway track transitions from plain-line track to a bridge abutment/tunnel base are considered. The effect of the transition length and the train speed on the track-train performance is investigated in terms of the rail-wheel interaction force and the train body acceleration. The presence of a track fault in the transition zone is also considered and the effect of the void size and train speed on the train-track response is presented. When comparing the observed performance of the transition zones to the simulated ones, it can be seen that the proposed model can give a comprehensive insight into the mechanics of railway track transitions.