A backing device, adapted to equip an axlebox comprising a bearing unit and supporting an axle. The backing device comprises: (a) an inner ring having an inner surface and at least one outer surface; (b) at least one outer ring having an inner surface facing the outer surface of the inner ring; and (c) a tightening component inserted inside at least one of the inner ring and the outer ring. When actuated, the tightening component presses the inner surface of the outer ring and the outer surface of the inner ring against each other and narrow the inner surface of the inner ring by elastic deformation thereof. The axlebox can be integrated into a vehicle. Mounting and dismounting methods are described herein.