I found the David G 4x8 Layout on YouTube
I like the layout but was bothered by the single return loop. Also after building it in SCARM I was concerned with the incline %. After playing with it for hours and adding few inches to length I came up with this layout. Please critique and let me know how plausible the 3.9% slope will work.
I can only add 1 image
A 3.9% grade is fairly steep, but given the size of the layout, you won’t be running long trains I suspect. I have grades that are 2.5%, and I can run fairly long trains, so any reasonable locomotive should be able to pull most anything you put on a 4x8 layout.
Welcome on board Rick_Cantu
David
Welcome Rick! I am curious, given your original plan for a 4x8 layout, and assuming you would utilize a 4x8 sheet of plywood, how you plan to add that small amount at the end?
Regards, Chris
Welcome Rick, I’m trying to understand the elevations, do the numbers with the decimal represent inches above the table? I built my grandson an MTH set up on a 4x8.
Because I have a 2X4 base 8 inches in around the bottom, I plan to add (3) 2X4’s to make the extension. I was thinking of adding a 12" piece. for a 4’x9’ total
Yes the small boxes are the elevation. I realized the pic posted was wrong for the inner loop elevations so here is the corrected one. This layout will fit on 48"x105" hopefully
Thank you David. 
