Fig xA Coupled train ndash

Fig. 6. Single layer track model (continuously supported).Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 7. Two layer track model (continuously supported).Figure optionsDownload full-size imageDownload as PowerPoint slide
To facilitate the inclusion of sleeper effects, discretely supported models were also developed [61], [62] and [17]. Fig. 8 shows SCH772984 Timoshenko beam discretely supported by individual sleepers with viscous damping.
Fig. 8. Two layer track model (discretely supported).Figure optionsDownload full-size imageDownload as PowerPoint slide
It should also be noted that the track support conditions (subgrade) have a significant effect on track stiffness and therefore have been found to affect track response. For the models previously mentioned, the track base has been assumed rigid. Although this may be suitable for tracks where the supporting material has a stiffness comparable to the track [63], discrepancies occur when the supporting material is soft. Therefore research has also been undertaken into modelling the subgrade as an elastic half-space [64], [65], [66], [67] and [68].