Virtual Coupling of Train Sets (VCTS) offers a promising way to boost railway capacity and flexibility, but it demands reliable, high-performance and safe wireless communication between trains and control centres, as well as between train sets. Current centralized systems like Euroradio are not suited for VCTS’s decentralized architecture, making a dedicated safety layer essential. This paper presents a Coloured Petri Net (CPN)-based framework to assess the reliability of Train-to-Train (T2T) communication, focusing on 5G NR V2X. After introducing VCTS architecture and dependability analysis methods, we detail our CPN model and performance metrics. Simulations reveal that higher message loss rates (MLR) significantly reduce reliability, highlighting the need for robust error handling. In the absence of VCTS-specific requirements for the wireless communication performance, we use automotive benchmarks (3GPP V2X, 5G AA) for evaluation. Under low MLR, the system meets these performance criteria.