For the purpose of improving the present seat reservation system for railway services, an experimental method utilizing a highly advanced computer and communication systems is proposed. The proposed method is based on transportation capacity in certain hours. A reservation is made tantatively in advance with no train and seat appointed explicitly. The reservation is confirmed at the time the passenger arrives at a station, and the most favourable train and seat are then assigned. The merits of this method, such as an effective use of transportation capacity and a changeability of plans on both sides, passengers and railway companies, are discussed. And a simulation based on M/M/1 model to formulate the movement of passengers and trains is intro-duced. The results of simulation, such as a variation of waiting time of passengers are shown.