Older railroad tracks utilized 20 m long rail segments. The large number of joints was the source of impact, damage and noise. To alleviate this situation continuously welded rails have been increasingly used. However, instability of the track, especially in the lateral direction, due to temperature variation and earthquake has become a major problem. In this paper a three-dimensional model of the track is used to investigate the said problem. The results of the study show that buckling of the track is likely in tracks that have been weakened by earthquake shaking and a sinusoidal shape is valid for homogeneous tracks only.
