Personally, I'm having trouble interpreting your design from the picture. It looks like the yard and engine roundhouse will be on an upper level with the mainline leaving in one direction while the branch goes the other direction. Correct? Does the hidden helix act as an intermediate level down to the lower level with an oval / reversing loop? Any chance you'd be willing to post the Anyrail file for easier inspection of your plan? It is very intriguing!