Thanks. Here's a slightly different version just to clarify things, since it seems to me my use of "A" might be ambiguous... All of the track I showed goes entirely on the layout extension to the left, at "C". So on this one, you can see where your "A" connects in... on the right. The track marked "D" is a dummy track. It is the "other mainline" that you interchange with, but you never actually run trains on it. It's just scenery. The stuff at "E" below the blue line might not actually be modeled - it's off the layout in the operator's lap - but its presence is implied by the alignment of the track "D" and the spur coming off the siding. Note that I shifted track "D" (used to be "A") to show that it doesn't have to (and probably shouldn't) cross both the main and siding. The turnout to the industry at "C" could be anywhere along the main and the spur could also cross the "other main" if you wanted. Note also that this is NOT a true wye. It's a crossing. You could make it a wye by adding another curved track to the right of the other main as Kursplat mentioned, but then you'd have to get permission from the other RR's dispatcher to use it. In other news, adding the second connection at (your) "A" to form a wye between the yard lead and your existing layout is probably a good idea. I don't think I'd do the second-yard-lead extension, though. Just a simple wye.