The lower deck 

I have left this alone at the moment as I want to get all the messy work on the upper deck done, although the plan will remain pretty faithful to the original except that some of the sidings will be longer and spaced out a bit more.

The upper deck

(Note plan is slightly incorrect its 4 feet shorter than it should be, a new plan has been drawn and has yet to be uploaded)

This part of the layout was originally inspired by the plan but seeing other layouts I have decided to keep it simple, a single track main with a siding to a cement complex based on Monolith, and another siding off to a wood processing/ lumber mill. These 2 industries will have their own workings of about a dozen cars each which will have to be switched.

Access to the upper deck is via a helix (inside 34" outside 38") with a 1.4% gradient.

Red is Visible track

Green is Hidden track

Buff is Walkways

although not drawn the upper staging yard will continue thru 90 degrees along the back wall