Abstract: Objective: With the development of urbanization in China, urban rail transit becomes an important transportation means, gradually demonstrating a trend of multinetwork integration and networking development. In the context of ′fournetwork integration′, there is the demand for crossline interoperability. To address its technical barriers, it is necessary to analyze and study compatibility solution schemes among different formats of signaling systems.Method: The main functions of CBTC (communicationbased train control) system and CTCS (China train control system) are introduced, and the difference between these two signaling systems is comparatively analyzed. The overall architecture of the dual onboard equipment scheme is presented, as well as the operational procedures for manual driving conversion scheme and autopassing neutral zone scheme. It is pointed out that there are no technical barriers to achieve crossline operation between CBTC and CTCS from the technical perspective, however the key factor for achieving ′fournetwork integration′ lies in the establishment of management systems and certification modes. Result & Conclusion: Two solutions of dual ground equipment and dual onboard equipment are proposed for CBTC and CTCS compatibility, and their advantages and disadvantages are analyzed in detail. The study on dual onboard equipment solution is carried out, providing an elaborate explanation of the business process and supporting plans for manualpassing neutral zone and autopassing neutral zone. The advantages and urgent problems faced by the dual onboard equipment scheme are thoroughly examined.