Shaped mounting rail

A mounting rail comprises a single sheet of steel plate shaped to completely form an elongated approximately C-shaped hollow rail body having a length dimension (L) with an opening extending in the length dimension affording access through the opening to the interior of said hollow rail body for supporting various elements from said rail body, said rail body formed by a planar first wall form by spaced apart webs (4a, 4b) containing said opening, an opposite planar second wall (2) and a pair of spaced side walls (1a, 1b) disposed at right angles to said second wall (2) and to said first wall (4a, 4b) and having a wall thickness (d), said side walls (1a, 1b) bent inwardly at the ends thereof spaced from said second wall, said side walls (1a, 1b) having groove-like recesses (3) in exterior surfaces thereof and spaced between said first wall (4a, 4b) and said second wall with a depth (t) inwardly of the exterior surfaces of said side walls (1a, 1b) and the depth (t) being less than the wall thickness (d) of said side walls, and the inwardly bent ends of said side walls forming said first wall (4a, 4b) being bent inwardly toward one another and doubled over into surface contact with inner ends of said doubled over walls (4a, 4b) being spaced apart transversely of the length dimension (L) and having a thickness approximately double the wall thickness (d) of said side walls and forming therebetween said opening, and said recesses (3) have a width (b) perpendicular to the length dimension (L) in the range of 0.25 to 0.75 times the height (h) of said side walls extending between said first (4a, 4b) and second walls (2).