On the plan below, I'm having thoughts on whether the insulfrog single slip (lime green) should be isolated as a seperate section, or could it be part of the red section, leaving the individual sidings as seperate sections ?? On the Peco instructions, it reads "On this slip the two frogs are electrically seperated from the rest of the rails, and in every situation their polarity needs switching using either PL-13 or PL-15 switches". The diagram below which comes with the above text, shows the single slip being isolated from the rest of the layout. I can understand this as if I were running by-directional trains, but this is only a plank with no passing loops, nor trains traveling in opposing directions at any one time. Looking at this diagram, I would say that it is for an 'electrofrog' slip and not an 'insulfrog' slip. Cheers, Gary.