The "branch line" that runs through Freeport,was NOT a branch line for roughly 150 years(ended in 1984),but the Lower Road,from Portland to Waterville via Augusta. This and the Back Road,via Lewiston,met again at Waterville. Brunswick was a major rail junction,with a Lewiston Lower Branch(inactive since late 1987) radiating from there,the active Rockand Branch,and of course the Lower Road(currently not active).
Guilford has been "tardy" in making connections with the current operator of the Rockland Branch,Maine Eastern(I was railfanning in Brunswick today,and Guilford has not sent a train to Brunswick,in well over a week. one was due today,after Guilford finally ran a "critter plow" up there yesterday;todays promised train was very late,if it showed at all!!(Maine Eastern engine waiting patiently,and close to 30 cars awaiting pickup by Guilford) This is NOT good for the cement traffic from Thomaston,that Maine Eastern is trying to increase! But once the few remainingl debris are removed from the Maine Yankee Atomic Power Plant site,there will be virtually NO consignees on the Rockland Branch.
When the line from Rockland to Brunswick was being rehabed,and Maine Yankee was first being demolished,2-3 Guilford trains a week,but not any more! Ironically,the Lower Road,from Royal Jct. in Cumberland,where the Back Road(Guilford freight mainline) 'split",was rehabed a little this summer,for "1" Amtrak special train",with speeds (except through crossings in Downtown Freeport/Yarmouth) (,up to 25 mph!!!-from 10 mph.
Sorry for the long post,but I don't think you will see "regular" passenger service from Portland to Brunswick for quite a while.(unless we continue to drive "trucks".wasting our imported fuel!!!). There would be a slight demand for Portland to Freeport(for the many shopping outlets),but not much to do in Brunswick. I wouldn't rate the weekend excursion trains Brunswick to Rockland last year a great success either. So,who knows!? Bud