The researchers analyzed how building a new highway over an existing railway tunnel affects the tunnel's displacement and stress. They used a 3D model to study a specific tunnel in China. The study found that the maximum additional displacement of the tunnel was 1mm, the maximum additional stress was 1810 kN·m/m, and the maximum horizontal displacement of the highway excavation face was 41.0mm. By carefully planning the construction and monitoring it closely, the railway can operate safely. The researchers suggest conducting the excavation in a systematic way and making adjustments based on monitoring data to minimize negative impacts on the tunnel.