The upper deck represents the Maine Central RR mountain division track in the White Mountains of New Hampshire between Crawfords and Intervale. Beyond Crawfords is St. Johnsbury Vt., represented by the upper-deck staging in the workshop area at the bottom of the trackplan. The MeC is joined by the Boston & Maine RR at Intervale. The MeC continues to MeC Portland, Me, staging (at the upper left corner of the plan) while the B&M descends a helix to the lower deck.
The small engine facility and yards at Bartlett provide helper service for the climb to Crawfords. Helpers are not turned, but back down the grade to Bartlett. A wye that once provided interchange for the Bartlett & Albany, now serves in place of the turntable that was filled-in when the MeC obtained several over-length 2-6-6-2's from the B&M in 1912.
In the trackplan, I have extended the yard lead and the tail track of the wye into hidden trackage. The hidden track will not be used during operating sessions, but provides loop-to-loop and folded-dogbone operation of the upper deck for display, test and momentary owner lapses into model railfanning :-)
Missing from this trackplan are Glen, Bemis, Sawyers River, and Carrigan, due to lack of space.
The lower deck is much more freelance, but represents the general feel of the Boston & Maine trackage between Rollinsford, NH and Exeter, NH. The track begins with Boston, MA staging at the bottom of the trackplan. A tight helix between Boston and St. Johnsbury staging will allow empties and loads to circulate between ends of the layout.
The track will emerge at Exeter and proceed to Rockingham Junction where it will be joined by the Portsmouth branch. It will then proceed to Dover, where there will be some industrial switching. Leaving Dover, the track will disappear behind buildings in order to accomodate the deeper scenery of the upper deck at Frankenstein trestle. Track will emerge at the far side of the peninsula to proceed toward Rollinsford.
At Rollinsford (upper left of the trackplan) the B&M splits with the mainline continuing to Portland, ME B&M staging while the branch ascends the helix to the upper deck at Intervale.
Hidden track will again allow continuous operation on the lower deck for display and test running.