With the development of railway communication system and the rapid advancement of 5G technology, 5G-R (5G-Railway) is expected to become the next generation standard of railway communication system. As a potential frequency band of 5G-R, the propagation characteristics in classical railway scenarios of 2 100 MHz need to be studied urgently. In this paper, a 3D model conforming to the typical characteristics of the scenario is constructed, and the propagation characteristics of 2 100 MHz wireless channel in the semi-enclosed high-speed railway platform scene are studied based on ray tracing simulation method. Transmitters are deployed beside columns and escalators. Meanwhile, the parameters of propagation models are defined, and massive simulations are conducted on hand-held and vehicle-mounted mobile devices respectively. Finally, channel characteristics such as path loss, delay spread and angular spread are analyzed respectively, providing a reference for coverage power prediction, network planning and optimization of 5G-R deployment, which makes up for the shortage of research on railway application of this frequency band.