I have photos of a somewhat similar prototype situation (the former Youngstown and Northern shop facility) which is now Larry's Truck and...
I'm a RailOp user and have successfully used both Minirail and RailOp. I more or less alternate between the two. RailOp is very easy to use...
You didn't mention e-mailing Athearn to see if they had replacement parts -- I would try this, though I'm told they are running out of stock. You...