Railcar adapter, for connecting a railcar body to a bearing, comprising a bearing seat side secured to the bearing and a frame seat side secured to a bogie frame of the railcar body, wherein the railcar adapter (20, 30) comprises a top cover (21, 31) in contact with the railcar body, forming the frame seat side, a bearing seat (22, 32) adapted to be mounted on the bearing, forming the bearing seat side and at least one damping element (23, 33) located between the top cover (21, 31) and the bearing seat (21, 31), and wherein the bearing seat has an inner surface in radial contact with the bearing and a flat outer surface having a central cutting adapted to receive the damping element and the top cover, characterized in that: the central cutting is delimited by two parallel first lateral surfaces (24a, 24b) perpendicular to a first axis of symmetry (A 1) of the adapter, two opposed first rounded surfaces (24c, 24d) connecting said first lateral surfaces (24a, 24b), and a bottom in radial contact with the damping element and wherein the damping element is delimited by two parallel second lateral surfaces (23a, 23b) perpendicular to a first axis of symmetry (A 1) of the adapter, two opposed second rounded surfaces (23c, 23d) connecting said second lateral surfaces (23a, 23b), a substantially flat inner surface adapted to come in radial contact with the bottom of the bearing seat and a substantially flat outer surface, each second lateral surface (23a, 23b) being provided with first cuttings and each second rounded portions (23c, 23d) being provided with second cuttings, and in that: the top cover is delimited by two parallel third lateral surfaces (21a, 21b) perpendicular to the first axis of symmetry (A 1) of the bearing seat, two opposed third rounded surfaces (21c, 21d) connecting said third lateral surfaces (21a, 21b), a substantially flat inner surface adapted to come in radial contact with the substantially flat outer surface of the damping element and an outer surface adapted to come in contact with the railcar body, the substantially flat inner surface of the top cover having a plurality of first and second radial portions (21f, 21g) extending radially inwards and respectively adapted to cooperate with the first and second cuttings (23f, 23g) of the damping element. the central cutting is delimited by two parallel first lateral surfaces (24a, 24b) perpendicular to a first axis of symmetry (A 1) of the adapter, two opposed first rounded surfaces (24c, 24d) connecting said first lateral surfaces (24a, 24b), and a bottom in radial contact with the damping element and wherein the damping element is delimited by two parallel second lateral surfaces (23a, 23b) perpendicular to a first axis of symmetry (A 1) of the adapter, two opposed second rounded surfaces (23c, 23d) connecting said second lateral surfaces (23a, 23b), a substantially flat inner surface adapted to come in radial contact with the bottom of the bearing seat and a substantially flat outer surface, each second lateral surface (23a, 23b) being provided with first cuttings and each second rounded portions (23c, 23d) being provided with second cuttings, and in that: the top cover is delimited by two parallel third lateral surfaces (21a, 21b) perpendicular to the first axis of symmetry (A 1) of the bearing seat, two opposed third rounded surfaces (21c, 21d) connecting said third lateral surfaces (21a, 21b), a substantially flat inner surface adapted to come in radial contact with the substantially flat outer surface of the damping element and an outer surface adapted to come in contact with the railcar body, the substantially flat inner surface of the top cover having a plurality of first and second radial portions (21f, 21g) extending radially inwards and respectively adapted to cooperate with the first and second cuttings (23f, 23g) of the damping element.