Edge computing, as a key technology of the intelligent railway 5G network, it sinks data caching capabilities, traffic forwarding capabilities and application service capabilities to the edge of the network, effectively meets the low latency, large bandwidth, and massive connection requirements of intelligent railways to support intelligent rail transit application. However, due to it changes in physical location, business types and other aspects, and the complex external environment of the railway scene, highly dynamic, and low credibility, the edge nodes of the intelligent railway business are faced with new security challenges. Combined with the current research status of 5G edge computing security, the security threats faced by railway 5G edge computing are analyzed based on the analysis of the four aspects of terminal, edge network, edge node and edge application. On the basis of detailed security requirements and challenges, and standard progress, the research methods and evaluation indicators are summarized that can be applied to railway MEC safety. Combined with the characteristics of railway 5G edge computing, this paper proposes railway MEC end-to-end safety service solutions and the development direction of future intelligent railway MEC security research.