It was definitely the TAM Valley unit. It will fit in a large HO locomotive, but a road switcher or smaller would be problematic. Most likely even in S some of the weight would need to be replaced with a battery - note that the On30 Forney shown is a pretty small model, not much larger than S.
The point is that it uses the DCC system, including the hand held controllers. The NWSL system has more proprietary components. Pieter E. Roos
