This paper presents an analytical method to investigate the three-dimensional elastic vibration problems on a railway carbody. The carbody is modeled as a simply-supported non-circular cylindrical shell without end plates. Transfer matrix method is applied to the analysis model. The model has an advantage of the matrix size for calculation. Therefore we have applied this model to simulate the effect of the rigidity of the connecting part between roof and side panel. As a result, it is found that amplitude ratio of floor to roof can be reduced when we set the rigidity of the connecting part between roof and side panels to higher value. And it is also found that the natural frequencies become higher at the same parameter changing.
