A well-designed timetable should not only be able to satisfy travel demand, but also be able to remain reliable when exogenous delays happen. Thus, how to analyze whether a timetable is stable becomes an important issue for railway operators. Among all methods to evaluate timetable reliability, statistical methods are only suitable for existing timetables, whereas analytical models can not consider the detailed train operation rules. Thus, this study develops a simulation model to analyze timetable reliability, while taking into account the influence of random delays. In addition, this mod can be applied to compare the reliability variation between existing and revised timetables. Finally, a real railway system is employed to investigate the influence of various factors on reliability. The empirical analysis shows that the results comply with our prior knowledge.