Hooray! another URR fan in the MARC area! Here are a few thoughts, and comments.
1. I re-iterate what was said above about considering Gargraves. P&LE/URR means mills which also means industrial trackage. Industrial trackage is usually nor on a roadbed and often buried in asphalt/concrete/dust.
2. You would be hard pressed to find a straight tangent of track in the Mon Valley. If you did, a large steel trestle was probably involved. Curvy track rules the day
3. different railroads were often separated more by elevation than distance.
4. It was recommended above to hide reversing loops. Very true, although as "everything has a prototype" I believe there was at one point a loop at Browns Dump. (That would be the slag dump, not the current dump at the bottom that was once the great Century III mall 😥 )
5. In the "Amtrak" era, Both the Mon Valley line (PATTrain) and the Brunswick line had RDCs as part of their passenger fleet. Later they each used refurbed coaches (Former C&O and PRR respectively) in push/pull service using F series diesels. Prior to that, either small B&O passenger trains or go big and run the Capitol Limited.
Given those items, My mind goes to this suggestion. Put a grade on each outer loop to gain some elevation for the back half of the layout. On the right side, continue the curve, to bring the mainline closer to the front of the table by a foot or so, then put a yard behind it. Perhaps model a Steel mill along the wall. The back part of the main can continue more or less to the left wall before dropping back down. Sort of a dogbone, with the left loop bent down. I would put a mountain on the right side, and would find a way to put a small reversing loop or staging track for the URR in mountain. I would then have it switch onto the inner main in front of the yard, then switch back off as the left side was reached, to a spur for a slag dump
Yeah.. I know I hear people saying that mills were usually at water level, but Irvin works, on the URR, was on a bluff overlooking the Mon.
Attached is a very bad hacking up of your plan with some of some of my ideas.
