Some of these gears are "Locktited" on. I made a special collar to hang the gear, and a cradle with padding to catch the motor gently.
Heat the worm and the motor drops out.
MTH is that way. Not totally sure of the K-Line, but I two-railed one with a Pittman 8000 series motor (in the firebox where God intended motors to be) and stitched up the belly. It was stunning, but seemed too small to me.