More from today (6/22/2019):
Here are some test fittings of track around the prospective hatch.
Track centers on the eastern approach will be 3.75" apart (15 scale feet, which is just an scootch wide for the Pennsy).
On the curve itself, the track centers will be 4" apart (16 scale feet). Hopefully we will not side-swipe 18" passenger cars.
In this photo, the ruler indicates the edge of the hatch and its location relative to the tracks.
More when I know it.
George