Abstract: Mounting structure for a bay of racks of electrical equipment, such as telephone switching apparatus which extends vertically between a support floor to almost the height of a cable runway extending horizontally between racks of the bay. Each rack includes at least one subrack comprised of sidewalls with horizontal separators joining the sidewalls. The separators mount switching modules in a slide-in relationship. One sidewall of a subrack is hinged to the cable runway to enable the subrack to be tilted away from the normal vertical position allowing access to a paired subrack and to cables connected to the tilted subrack.