The invention relates to a rail fastener for track systems, comprising a tensioning element (1) made of an elastic material, in particular hardened spring steel that in the assembled state is fixed in place between a retaining plate (3) provided on a sleeper (2) and a fastening anchor (4) such that the tensioning element exerts a retention force on the foot (5) of a rail (6) in order to hold the rail (6) in position, the tensioning element (1) being symmetrically aligned with respect to a vertically oriented plane of symmetry (7) that is perpendicular to the longitudinal axis (8) of the rail (6). According to the invention, the tensioning element (1) has two torsion legs (1a′ and 1a″), preferably extending essentially in parallel, in order to achieve stepped overload protection. The two torsion legs (1a′ and 1a″) are connected to one another on the side facing away from the rail (6) by means of a connecting section (1b), and a loop-shaped clamping section (1d′ and 1d″) is provided on each end (1c′ and 1c″) of the torsion leg (1a′ and 1a″) facing the rail (6). In the non-tensioned state of the tensioning element (1) the torsion legs (1a′ and 1a″) together with the connecting section (1b) lie essentially in a first plane (9), and at least a portion of the loop-shaped clamping sections (1d′ and 1d″) lie in a second plane (10). The second plane (10) is rotated about an axis (11) in relation to the first plane (9), the axis extending parallel to the sectional axis of the plane of symmetry (7) containing the first plane (9).