The operation of the China Railway Express (CRE) has diversified freight transportation between China and Europe, expanding the international freight channels in Chinese cities where CRE operates. However, the relationship between the evolution of China-Europe freight routes and the development of Chinese cities remains unclear. Therefore, we propose a potential model to assess the evolution of CRE routes and develop an indicator system to measure city sustainability. We employ a coupled coordination degree model (CCDM) and structural equation modeling (SEM) to determine the impact of CRE on the development of these cities. Findings reveal several key insights. Firstly, CRE has facilitated the expansion of China-Europe freight routes in Chinese cities, significantly enhancing the accessibility of China-Europe integrated inland transportation. Secondly, the growth of freight routes between China and Europe has exerted a substantial influence on the long-term development of Chinese cities, particularly inland cities. The positive relationship between route evolution and city development has strengthened over time. Lastly, the expansion of China-Europe freight routes indirectly contributes to the development of inland cities, primarily through stimulating innovation, industry scale, financial growth, and international trade. In contrast, coastal cities mainly benefit from the direct promotion of the international trade levels.