Abstract: This paper proposed a new-generation bearer network with high isolation, high reliability, and manageable and controllable characteristics to support the construction of the 5th Generation Mobile Communication Technology for Railway(5G-R). It compared and analyzed three mainstream bearer technologies, including Slicing Packet Network (SPN), IP Radio Access Network (IPRAN), and Optical Transport Network (OTN), and evaluated their performance in terms of slice isolation, transmission latency, and time synchronization through experimental verification and performance tests. The research results show that SPN technology deeply integrates the advantages of time-division multiplexing and packet switching, supports integrated service bearer from Layer 1 to Layer 3, and has key capabilities such as hard-isolated slicing, ultra high precision synchronization, and multi-service convergence. Therefore, SPN can effectively meet the high-security and high-reliability bearer requirements of railway 5G-R and existing communication services, and has good prospects for future deployment.