A large amount of fine dust containing iron (Fe) components is scattered by the movement of trains through a subway tunnel. The fine dust spreads to the subway platforms where they are inhaled by passengers, leading to a possibility of acquiring respiratory disease. In this study, a baffle dust collector, which is a type of inertial dust collector, was considered to be attached to the bottom of a train traveling through a Gwangju city subway tunnel to collect dispersed dust particles. To assure a certain level of air suction, a powered fan was installed at the back of the baffle dust collector, which comprised 12 parallel particle-attracting plates connected to perforated circular particle- collecting tubes. The air flow around the baffle dust collector was analyzed, and the volume of air flowing into the collector was predicted with respect to the train speed. Particle analysis was also used to predict the dust collection efficiency in the uniform-speed section of the subway tunnel where the train travelled at a constant speed of 70 km/h, and the results were compared with wind tunnel measurements. It was found that the air flow rate into the baffle dust collector at the constant train speed of 70 km/h was only approximately 2.1 % higher than that in the low-speed section of the tunnel where the train moved at a speed of about 10 km/h. In addition, the cutoff size of the suctioned particles at a speed of 70 km/h was determined to be 7.8 μm.