Optical rail system

An integral optical rail comprising a uniform cross-sectional shape throughout its length, two spaced-apart top longitudinally extending flat bearing surfaces, a bottom longitudinally extending flat bearing surface parallel to said top surfaces, each of said top surfaces being equal in width and the overall widths of the top and bottom of the rail being equal, four flat locating surfaces on the sides of the rail, each locating surface extending towards a central plane of the rail perpendicular to the hearing surfaces from a line contiguous to the edge of a said bearing surface at an angle of substantially sixy degrees to the horizontal for cooperation with corresponding surfaces in grooves of couplings and optical carriers, said grooves also having surfaces for cooperating with the bearing surfaces, a fifth and a sixth flat locating surface each extending inwardly and towards an outer side of the rail from a line contiguous to an inner edge of a top bearing surface at an angle of substantially sixty degrees to the horizontal, plural portions of said rail cross-section in a plane parallel to the bearing surfaces narrowing to a width in the range of one third to one fourth of the width of a top bearing surface at two locations spaced from a central plane perpendicular to said bearing surfaces, and a horizontal web extending between regions contiguous to said locations.