@Lehigh74 posted:Mine is set up like Ken’s. Only the sidings are switched. Not sure you will need two TIUs. I have 4 loops with about 120’ of track each. Also, a hundred or so feet of siding. All on one TIU fed from two PW ZWs.
If I had two ZWs, I'd agree, but I'm using 2 LWs and 2 RWs. They're lighter in output, so I went with one per channel, two TIU channels per mainline. Might be overkill, not sure, but I'd rather have two much power for two engines per mainline than not enough.