Railway station design has as a starting point the knowledge of all possible running conditions that really can verify at long term; in order to design railway stations, a methodology to test running conditions is proposed in this paper. Running is defined by means of hypothetical time tables, to each of them different probability functions of delay are coupled. The method allows to analyse station, during successive time intervals, in a synthetic way. In order to evaluate probability of both served and at signal waiting train number, as well as the respective mean values, the model takes into account of compatibility conditions between routes. In a numerical application a comparison is made between a preceding model, based on the hypothesis of random arrivals, and this one.