Abstract: In single-track railway sections, there is a close relationship between the traveling density of passenger trains and their traveling speeds. In this paper, an in-depth analysis is made of the crossing, overtaking behaviors, and traveling speeds of passenger trains on single-track railways, and a general rule reflecting the relationship between the traveling speed and the traveling density is found out. Through a computer simulation, the reasonable scope for the number of passenger trains to be operated on Xiangfan-Huaihua line is obtained. This work can afford a theoretical reference for determining the reasonable number of passenger trains on other single-track railways.