Just for ideas, this shows a Marx double-reduction motor I fit into a prewar American Flyer Minnehaha loco, which has a fairly small body shell. The motor has to pivot inside the shell so I improvised a hanger bracket. Part of the E-unit frame is cut away for clearance. Point being, this is a fairly compact motor unit which can be adapted to other small locos.
Another idea, a prewar motor which I put in a Lionel #259 loco has smaller drivers which would look right on a switcher loco, and it fits into a somewhat smaller body shell. I removed the E-unit on this one and installed a manual switch instead.
