I don't think you want to have two Powerhouses in parallel (or series for that matter) unless they are interfaced by a device designed to do that (such as the now out of production TPCs). You can certainly have each Powerhouse powering a separate loop or stretch of track. I'm not sure what your friend is doing, but hopefully it's not running two Powerhouses through a single TIU channel. That would not be good in terms of the TIU's continued survival. If I've misunderstood your question, I apologize.