Here are some pics of the subroadbed for the Chattahoochee Yard, or at least most of it. That short train is some of the few remaining equipment I have from the old days. I haven't completed the portion at left:

This closeup shows where the wye will be located. Engines will turn on the wye for their return trips to Tallahassee or Pensacola:

Here's the west end of the yard. On the right, the mainline follows the helix up to Cottondale, which will be directly above that boxcar. There's room for a few staging tracks on the left, and in between is a curved extension for the yard lead:

So finally a little more progress. Next up is the other helix, then I plan to lay track on this portion before building up the roadbed for the middle and upper levels.