Roadbed, track, wire and switches(!) in main staging

Steady progress. Much of the reason the staging loops went so slow was that there was a lot of repetition:

1. Measure/test latest construction
2. Move staging loop section to side desk, make adjustment (or redo construction)
3. Move back to corner desk, measure and test again.
4. Repeat 2.
5. Repeat 3.

Plus I really had to get the staging loops right the first time because once locked in place they will be very hard to modify.

Now I'm able to do stuff right on the benchwork, and to do large sections at once. Below are two photos, this first one is from January 26 (two days after the previous layout photo):

The above photos shows the subroadbed for the lower two tiers is in place (after measuring and adjusting to make sure it was level), the lower level roadbed is in place, track has been laid for the lower tier return track (nearest to the layout edge) and guidlines have been drawn for the other track.

This photo was taken 5 days later on January 31:

Now, I'll admit that at first glance it doesn't look like much has changed. But look more closely and you'll see that many tasks were completed:

1. The most obvious is in the center of the photo, where switches and track have been laid for the lower tier, and at the time of the photo more track was being glued down. I prefer to weigh the track down during gluing, instead of pining it down, except where curvature requires pins. This is because pins have a tendency to cause the track to be unlevel when they are pushed in too far, especially near short track pieces like switches and rerailers.
2. Blue roadbed has been put in place on the middle tier. You can't see it from here, but this required some adjustments in the area of transition from the lauan plywood loop to the 1/2" plywood to make sure all was level.
3. The support piers for the upper level entry track, near the wall, are now all in place. I waited to do this until I had the mid level subroadbed set in place, because I wanted to verify everything would fit before adding the rest of the piers.
4. The power bus and two terminals are in place. There is one terminal in the lower left of the photo. The other is attached to the joist near where the lower level roadbed splits to form the loop. There are also two feeder wires in place (K1 and K2) and lower level track that is set in place has been tested.
5. The blue/yellow pair of Auto Reverse (AR) wires is now attached along the front edge of the layout, and extends all the way to where the power cabinet will be (not in photo). This is for the lower tier return track AR section.

So, of course you know what happened the first time I tested an engine on the lower level track -- I found a problem on the lower level staging loop.

The AR blue/yellow wire is 16 gauge, as I'll describe in an upcoming wiring post. On the loop I chose to attach it directly to the rail as a measure of simplicity, but I probably should have transitioned to 22 gauge wire just in case. It turns out that on the wire connection for the outside rail of the lower tier the wire sticks up just enough to cause the snowplow of a Kato SD90MAC (the longest diesel actively in service on railroads today) to bump the wire and get stuck. Now, of course I tested this when I first built it, but I used a Kato SD70MAC (just slightly shorter) as well as a variety of other locomotive. Turns out that the slight difference in size is just enough.

I'm debating what to do. You see, it only affects this one locomotive type (I've retested with all the others), and only when the locomotive is facing forward going in one direction -- the opposite of the direction of this one-way track. I will fix it, as it bugs me. But I have time to think it through first, as this wire connection is -- and I know Murphy is laughing -- in the exact worst place for maintenance access on the staging loop.