In this study, resonant vibrations of two-span railway bridges subjected to high-speed trains (HSTs) are studied. The continuous beam is modelled by using Bernoulli-Euler beam theory, and the train is considered as a series of moving concentrated loads. The dynamic response is obtained analytically by using the assumed mode method. Effects of the speed parameter and the span to car length ratio on the response are examined. Numerical results show that the above mentioned parameters play very important role on the dynamic behavior of two-span bridges.