Don't tell anyone, but here is a little known secret of Trainz: My little McCall Yard switching layout is actually built on the Interstate DEM! The main yard is at the site of the SOU / L&N Yard in Appalachia and the branch that runs North from McCall Yard from the wye (which is exactly where it should be) to the auto factory and beyond is the trackbed of - you guessed it - Interstate RR. The auto factory is pretty much on the site of Andover Yard, which was Interstate's home base. The industries beyond the auto plant are on one of the coal branches that radiated into the hills from there. The 'Southern Pacific' branch that runs north / south on McCall is the SOU / L&N line to Big Stone Gap...
Andy