Abstract: Objective Currently, city railway development in China is still in its early stages. There is a lack of theoretical analysis and empirical support regarding rolling stock selection, fire protection design, and emergency evacuation/rescue in long and deep tunnels. Therefore, relevant research is urgently needed. Method Taking the Shanghai Suburban Railway Airport Link Line project as case study, a tunnel-train model corresponding to the project is constructed. FDS software is adopted to obtain the distribution law of temperature and carbon monoxide concentration. Result ＆ Conclusion In the absence of longitudinal ventilation, hightemperature smoke from a fire will diffuse freely within a single-tube double-track tunnel, forming a symmetrical distribution of temperature, visibility, and carbon monoxide concentration fields around the fire source. Under longitudinal ventilation conditions, the temperature field within the burning compartment is only slightly affected, but the smoke diffusion characteristics within the tunnel change significantly. The temperature along the longitudinal evacuation path in the tunnel drops substantially, providing a safer environment for passenger evacuation. However, the longitudinal ventilation also accelerates smoke movement within the burning compartment, causing a slightly earlier coming of critical thresholds for visibility and CO concentration than those in scenarios without longitudinal ventilation. Under conditions where the compartment is sealed, in a relatively short time the temperature and CO concentration at featured heights can reach dangerous critical state threatening passenger evacuation safety. If a train loses power and is forced to stop in the interval rather than reaching a station, evacuation can be carried out through the nearest link passage into the no fire tunnel interval, then from there to a safer area. Additionally, evacuation platforms allow passengers to disembark and walk within the tunnel; the platform height is level with the compartment floor. In emergency situations such as fires, ventilation shafts in city railways can rapidly exhaust smoke, reducing the impact of smoke on passengers and rescuers, shortening the affected ventilation section, and providing favorable conditions for emergency evacuation and rescue operations.