A platform comprises an array of slots for mounting electronic modules. Side rails are mounted on the platform. A side rail defines at least one outer edge of a slot. A central structure mechanically supports corresponding first electrical connectors for the slots. In a slot, a tray holds an electronic module. The tray comprises a second electrical connector supported at or near an interior end of the tray. The tray is secured laterally by at least one of the side rails. The tray is secured at or near the interior end by the second electrical connector that engages the first electrical connector. The tray is secured at or near an exterior end by an outer fastener associated with a floor of the platform.