Safety structure for protecting a railway line includes a fencing on supports resting on the track bed. These supports are connected to a rail of a railway line. The connection is effected by magnetic force. At their free ends, the supports have permanent magnets having a shape allowing them to engage the web of a rail. Due to the significant length of the supports, it is possible to apply a great torque to the magnets when the other end is engaged, that is to say that end which is turned away from the permanent magnets, as a result of which the magnet slides away along the web and can be detached therefrom. The magnet may consist of a number of magnets stacked on top of one another. The magnet is preferably arranged so as to be slightly displaceable with respect to the support to provide compensation for an uneven surface.