John,
We hooked up my Legacy base on Clem's layout last Saturday. He is DCS and his layout is folded back on it's self to make a single loop of track 3 scale miles long. Over half of it looks like a double track main, but is not. He uses all four channels of one TIU, rev L - I believe, as four blocks on his loop. We connected the four black TIU output terminals together and connected the Legacy base there. We ran up to six trains at a time, a mix of DCS, TMCC, and Legacy. The only problem was when Clem tried to bring out his "Lashed up MU" DCS train. We lost control of the DCS engines on the track. Makes for interesting times, thanks for the DCS emergency stop - kills all power to the track. Clem has seen the MU problem before and recognized it. You may need to talk to him to get more details. We never checked signal strength. You can see his layout on the "Detroit 3 Railers" October Meet thread.
