To assist in determining the base station spacing for the new generation of mobile communication systems for 5G-Railway (5G-R) in complex railway environments, a link-level transmission rate simulation technology is proposed. This technology relies on various empirical propagation models to obtain the path loss of electromagnetic waves in different scenarios along the railway line, thereby assessing the Reference Signal Received Power (RSRP) of the wireless link. Based on the obtained RSRP data, link-level transmission rates are calculated by using the Monte Carlo simulation method. Simulation results indicate that in open-field scenarios, base station spacing can be set between 2 000 meters to 3 000 meters, while in urban and complex terrain environments, the spacing should be reduced to maintain performance. This technique accurately reflects the signal transmission characteristics of 5G-R systems across various scenarios, including the changes in transmission rate and RSRP with different base station spacings. And it provides a scientific basis for future base station deployment planning in 5G-R systems.