The I&M group was the holding company that owned the various railroads affiliated with the Illinois & Michigan Railroad. When it was a separate company, it owned the I&M, the south end of the Ann Arbor, and the Chicago South Shore & South Bend. And after the Delaware & Hudson & Ontario Southwestern took it over, they left the corporate structure intact while unravelling the horrible mess that was its finances.
After the takeover, the railroads it controlled were transferred to other Parsons Vale subsidiaries (the I&M was transferred to the CSS&SB, which was then transferred to the PV&T, and the Ann Arbor ended up in the hands of the Ontario Southwestern.)
But the I&M group also had moderate real estate holdings, so the now derailroaded group was converted into a real estate subsidiary to manage the the Parsons Vale’s railbanked, reserved, and abandoned rail corridors (The CTRC project is, for example, playing merry hob with the old OSW mainline across Southwestern Ontario; large chunks of that mainline are in the process of being abandoned as the wires reach across the province, and that newly vacated land will need to be either sold to other shortlines or stripped of rail and sold for other uses.)