I take it that this is a Lionel and/or MTH control related question. If that's the case, you're in the right church but the wrong pew. Try asking this on the ToyTrain Forum: http://cs.trains.com/trccs/forums/95.aspx
Also, when I tried to figure out what TMCC/Legacy were, I found the following discussion: http://www.modelrailroadforums.com/forum/showthread.php?t=14788