Thanks guys. My rough math was that I'd need more than 100-125 per mainline that my PW transformers are capable of if running 2 trains. 100-125W / 18V = 5.5-7.0A Thinking I'd need more than that two trains, especially if passenger cars, on the same mainline. But, as was pointed out, I can try it and see how it works. If insufficient, I can always break connect 1/2 of each mainline on the main level to a channel and add a second TIU for the elevated track.