After lots of hot glue, photo references of the prototype, and head-scratching, here's what the area looked like before the plaster cloth went on. It's a complex area - in that first shot you can see the 3-track staging yard under the Elmer's glue - it'll remain accessible from the access hole (which is framed out here). That track is at about 52" high. Below that, at 47", is a return loop running under all of this.
Then there's the creek, coming into the scene near the speaker (yes, I know, perhaps I'll move it much later when this scene nears completion). I had to figure something interesting to do w/ it, while evoking the prototype's sense. Using the actual creek's route, I copied that and also managed to route the creek around the access hole, twisting and dropping below the town and eventually under the big 45-A trestle.
And here's a number of shots of the scene after the plaster - where you can see the landforms emerging from all that cardboard. I'm playing with a number of variables here - blocking nearly all views of the access hole from normal viewing angles, adapting the prototype's landforms to my space, and giving the eye lots of interesting nooks and crannies to follow. The creek will - I hope - really draw the eye into the scene. And the fact that parts of that creek will be hard to see to only add to the visual interest.
These first couple of shots are from really high viewing angles - which you can't see in real life without a ladder. But they show how the creek, access hole, and everything else fits together.
Here is a view from slightly below normal viewing angles. The hill behind this bridge is higher than on the prototype, but it's hiding the access whole. And I think it'll work pretty well - evoking the very rugged terrain as you move away from the town of Ophir slightly and down under this bridge.
The bridge, btw, is about 65% of the prototype's size. The creek twists down and exits between the two right-most foundations. These are the three heavy footings for the lower bents of 45-A - they support their own set of heavy stringers over the creek - then the actual trestle bents for the bridge above were built on those stringers.
And another fairly high-angle view, showing the creek meandering below the town. There's also a dirt road coming up the left side of the creek, crossing narrowly thru a couple of bents of bridge 45-A. There's timber retaining walls supporting this road above the creek.
If you'd like to see photos of the prototype town and bridges, I have an extensive set of details & links on my Route Summary page - just scroll down to milepost 45 or so.