A screw anchor for concrete attachment to a railroad tie or solid track comprises external threads (16) disposed on the exterior of the screw anchor (10) and internal threads (18) disposed inside the screw anchor (10) for force-fitted connecting to a fastening element (30), wherein the screw anchor (10) comprises two sections (12, 14) adjacent to one another in the longitudinal direction, the first section (12) having a substantially cylindrical external shape and the second section (14) having a substantially conical external shape, and wherein the second section (14) is disposed between the first section (12) and an inlet opening (26) for the fastening element (30).