The scale of fire accidents in railway tunnels is a key point for tunnel fire prevention. The fire accidents in railway tunnels and the results of studies on the scale of fires around the world have been reviewed and analyzed in this paper. The causes for and the result of fire accidents in railway tunnels are analyzed, and suggestions are made to reduce the fire accidents. Factors influencing the scales of fires in railway tunnels are summarized. A series of countermeasures, including employing fireretardant materials for the trains, designing a proper disasterprevention ventilation speed, and decreasing the number of the opening windows as far as possible, are proposed. Based on these suggestions, a 15 MW steady fire scale is recommended for the simulation and evaluation of fire accidents in railway tunnels. 