Experimental investigation of tunnel temperature field and smoke spread under the influence of a slow moving train with a fire in the carriage

•A series of model tests of slowly moving train with a fire in the carriage was carried out.•The relation between the HRR of fire in a slowly moving carriage and the train speed was revealed.•The temperature variation characteristics in the tunnel under moving fire was obtained.•The driving force and spread rate of the smoke produced by slowly moving on-fire train was clarified.