Ok here is a first try at power distribution for this layout. Following MTH guidelines (at least I think I did?) and everyone's input, here is the result for now. Three separate power districts, feed by 14ga. stranded wire from three tiu outputs which will have over current protection and indicator lamps. Then tracks are feed by 18ga stranded wire from terminal strips to tracks with a method of switching power (yet to be determined) to isolate those blocks from each other for both engine control (shutting off engines not in use in round house or spurs) and fault isolation. I tried my best to color code things to help make sense of this potential rats nest. Labeling the wire runs maybe something along TIU-PD1 to PD1-T1-1,2 So this would be connection between the first TIU output to power district 1 terminal strip 1, terminals 1 and 2 Making odd always black return and even numbers red hot side.
Everyone, please let me know of better power distribution methods, labeling etc. Always a better way to skin a cat!