I’m still considering the two deck + mushroom dream plan concept as proposed a few years ago.  One consideration is the distance between decks.  Superimposing the lowest level grades under the upper level grades I can see the clearances.

Bigelow to Strong shown under upper deck

This above diagram shows the deck separation as the railroad circles the layout room.  Bigelow is proposed to be 36″ high and the International mill in Phillips directly above would be 55″ above.  That’s 19″ spacing.  Carrabasset at 39.5″ would only be 17″ below Phillips at 56″.  On around the layout, the spacing between track levels would vary between 15″ and 19″.  If the upper deck is 4″ think, that is 11-15″ gap for viewing.  Not too bad.  Looking up Tony Koester’s track plan, and it seems to have similar gaps and widths.  My memory of his layout is that it was very acceptable.

I would like to ease the grade to Bigelow, so I’m planning to extend the line, shifting Carrabasset to where Bigelow is and put Bigelow below Strong.  Next post I hope to consider this change.