A fire–evacuation coupled modeling and passenger behavior analysis in high-speed train carriages under the dynamic effect of fire

The interior of high-speed train carriages is enclosed, narrow, and elongated, which significantly deteriorates evacuation conditions during a fire. High temperature, reduced visibility, and carbon monoxide (CO) exposure can severely affect evacuation efficiency. This study proposes a fire-evacuation coupled modeling approach that quantitatively integrates the dynamic effects of fire products on passenger evacuation through the introduction of a speed coefficient. Based on this approach, the study investigates smoke spread patterns and evacuation behavior under four typical fire source locations: the corner, end aisle, middle aisle, and middle wall of the carriage. The results indicate that changes in fire source location alter the distribution of acceleration and deceleration zones, affecting evacuation efficiency. Compared with the corresponding control scenarios without fire-product effects, the evacuation time for the corner fire source is reduced by 21.8%, whereas the end aisle fire increases it by 22.7%. For middle wall and middle aisle fire source scenarios, evacuation times are slightly reduced. Crowd congestion in the carriage is more severe and prolonged in the end fire source. The influence of the fire source location on flow rate capacity diminishes with increasing distance from the fire.