Abstract: The disclosure is directed to a modular frame assembly for electrical and electronic components and a universal rail member used in its formation which permits fabrication of the assembly in various sizes and configurations. The rail member comprises an elongated web with longitudinal sides and edges. A pair of first ridge members project laterally outward from one side of the web and extend over its length in spaced, parallel relation. A pair of second ridge members project laterally outward from the opposite side of the web, also extending over its length in parallel, spaced relation. The second ridge members are spaced apart to engageably receive the first ridge members of another rail member in interlockable relation. At least one notch is formed in each of the second ridge members, the notches being transversely aligned, and sized and configured to receive the end of another rail member in perpendicular, interlocking relation.