Nickaix, that was how SHS did it in S gauge. Both highrail and scale wheels plus pilots were "in the box." Swapping is a simple 5 minute job, plus mounting two Kadee couplers on the scale pilots.. American Models makes the engines either scale or high rail, specified on purchase. Their diesels can be converted later with replacement wheelsets if desired. Its too hard to convert the steam engine drivers. I bought a lot of scale engines because in S they will run fine on all high rail track systems except original Gilbert and GarGraves track. Plus all engines and virtually all rolling stock made in S are 1/64th scale, only the detail level varies. In S, even the Lionel Legacy engines run on DCC right out of the box.
I think this would be much harder to implement in O gauge because of three rail. It would also only be meaningful to do with those models that are full 1/48 scale.
