If you are talking Stanton drives, ... I asked around a bit over the years and the consensus I got was using them for O Scale was asking the pony to pull a beer wagon.
Maybe a wagon full of Bud Lite?..................dilly-dilly.
I just finished installation of a Stanton drive on an HO Doodlebug...railcar. It was an old Hallmark model...zinc truck block casting had pestified...the open frame motor and sloppy gearing had been noisy, anyway.
It turned out to be the absolutely perfect solution for this sort of application. I'm sure it has enough power to pull an extra car or two, as did the prototype 'bugs.
But I would agree that these might be marginal, at best, for an O scale locomotive seeking to pull a couple dozen...or more...NMRA-weighted cars...freight or passenger. OTOH, an email inquiry to NWSL might yield a prudent piece of opinion. After all, they would be most negligent of their reputation to recommend one of their products for an application that probably would exceed its capability. Ya think, maybe?
As for DCC compatibility, my HO doodlebug runs perfectly...including crawl speeds. The pre-wired Stanton makes that installation easy. And, if you're into detailing interiors, the Stanton is an awesome solution. In fact, for conversion of an O3R doodlebug or RDC to 2-rail, it'd be an easy first choice.....IMHO.
FWIW, of course...
KD