Abstract: A structural member, e.g. a truss for erection of temporary structures, comprises a number of elongate elements disposed in spaced generally parallel relationship to one another with transversely extending elements therebetween, and an element extending longitudinally of the structural member has a formation extending lengthwise of it for engagement by an attachment member which is to be retained to the longitudinally extending element at any of a range of positions therealong. The attachment member may provide for connection of a safety element to the structural member, and be freely movable therealong in use.