A highly reliable ladder redundant structure networking scheme applied to train communication network was constructed, and the fault protection and redundant switching mechanism of the network were analyzed. For complex TCN such as ladder networks, a simplified dynamic fault tree analysis(DFTA) method based on K-terminal connectivity detection was proposed, and a binary decision diagram(BDD) was used to simplify the fault tree calculation process. The algorithm proposed comprehensively considered the system structure and dynamic repair of devices in the network and the influence of the topology on the network reliability, which simplified the modeling and calculation process of the fault tree model. The paper analyzed the proposed algorithm for the reliability of the trapezoidal redundant structure for specific examples. The results show that the ladder structure has an increase in the mean time between failures by 1 513.32 h compared to the use of PRP and 5 034.61 h longer than the use of HSR under the same scenario, which significantly improved the reliability. The networking scheme constructed in this paper and the proposed reliability modeling method provided new ideas for the structural design and reliability modeling analysis of the highly reliable train communication network.