The present invention relates to a motor assembly for railway axle comprising an axle (2) having a drive wheel (2a) rotatable around an axis (A). The motor assembly comprises a planetary carrier (3) fitted on the axle (2) and a toothed planetary gear (5) carried by the planetary carrier (3) and movable by rotation with respect to the latter around an axis (B) distinct from the rotation axis (A) of the axle. The motor assembly comprises a first actuating wheel (4) constrained to the axle (2) and movable by rotation relative to the latter around the rotation axis of the axle; the first actuating wheel (4) has a coupling portion (4a) actuatable by a first motor (8) and a gear wheel (4b) engaged via meshing with the planetary gear (5). The motor assembly comprises a second actuating wheel (6) constrained to the axle (2) and movable by rotation relative to the latter around the axis of the axle; the second actuating wheel has a coupling portion (6a) actuatable by a second motor (9) and a gear wheel (6b) engaged via meshing with the planetary gear. The planetary gear (5) is radially interposed between the gear wheels of the first and second actuating wheel. The present invention also regards a railway wagon comprising said motor assembly.