Abstract: The invention relates to a rail assembly adapted for an earth potential related magazine (1) which is constructed to accommodate a plurality of printed circuit boards, circuit boards having circuit components mounted thereon, or printed boards. An electrical contact rail (3b) has a U-shaped cross section wherein a first leg (41) is provided with a row of tongues whose outer parts are bent towards the second leg such as to form a row of electrical contact points (41c) which are intended for electrical coaction with an earth potential related layer on the circuit board, and wherein the bottom rail part (43) extending between the legs is provided with a plurality of mutually sequential contact tongues whose outer parts form a row or electrical contact points which are intended to lie against electrical contact surfaces (1b) belonging to and assigned to the magazine at a chosen contact pressure when the rail assembly is fitted, so as to obtain an earth potential relationship.