Due to uneven ground network coverage and unstable signal quality, it is impossible to achieve full, fast, and real-time monitoring of the railway transportation network, which hinders the rapid development of China's railway transportation network. At the same time, the integration of Low Earth Orbit(LEO) satellite communication and ground 5G has become a hot topic, and the fusion of the two can make satellite networks an effective supplement to ground networks. The current application of satellite ground fusion in 5G-Railway(5G-R) technology scenarios is relatively limited. This article first reviews the current research status and the development trends of railway satellite communication and satellite ground fusion networks, points out development trends, and then analyzes the communication needs of various businesses in railway communication systems. Based on this, a network architecture that integrates low orbit satellites with 5G-R networks is proposed, which not only fills the blind spots in railway communication network coverage, but also provides high-capacity information feedback. It can effectively ensure the safe operation of railway transportation and achieve information and intelligent management of railway transportation.