During track installation a few ties had to be cut back to expose enough rail to make good joints. But, to make things look right, individual ties needed to be slipped under the tie-free parts once all the rail was down. It looks a little less cobbled together once ties fill those spaces.
I drew a picture of the lower level electrical loops. One colour for each segment, blue, green and orange, as well as two black stubs for the sidings. The initial section of the upper loop is shown in purple over on the left. I'm toying with the idea of using some sort of linear arrangement for the control panel instead of a more classic blocky trackplan look so the panel can be slim and compact. I'll post a picture when I've made up my mind.
I then went ahead and drilled some holes for the wire. Next stop: soldering.