The present invention relates to a subsonic capsule train, comprising: a plurality of levitation coils disposed along a traveling direction of capsule trains on both sides of the inner surface of a tube opposite to both sides of the capsule trains; and null-flux-type levitation devices spaced apart from the levitation coils by a predetermined distance so as to correspond to the levitation coils, arranged on the capsule trains, and including a plurality of on-board magnets in which a pair of N-pole magnets and S-pole magnets spaced apart from each other are arranged along the traveling direction, wherein at least some of the pair of on-board magnets are variable on-board magnets, the variable on-board magnets are arranged in a 2x2 matrix, magnets adjacent to each other in the traveling direction and in the vertical direction are arranged to have different magnetic polarities and are spaced apart by a first air gap in the traveling direction, and spaced apart by a second air gap in the vertical direction, the first air gap and the second air gap are formed to vary so that an induced electromotive force is generated in the levitation coils, and a braking force is provided by varying the first air gap and a levitation force is provided by varying the second air gap.