Tom,
For those who may not know Tom Wheeler, he is a long time breeder of Barred Rocks and some of us on this thread have birds from his handiwork. Anyhow, it is generally thought that E.B. Thompson's Ringlet line lived on with Ralph Sturgeon and then with Frank Reese of Good Shepherd Poultry Ranch. (GSBR) If these birds kept without any outside additions is beyond my ability to know. Others may know many more details than I.
The so called Maine Line has many "forks" and some of it is pretty cloudy. There are a couple really good breeders in the Canadian Maritime provinces and in Maine and stock has crossed the border up there more than once. aoxa is a member here and has excellent birds from one of these flocks or forks or whatever you wish to call it.
Guy Roy is another northeast breeder who has my respect. Whenever I've seen his work, I see a lot I admire.
Tom, some 4 years ago, I got a trio out of the New England area that were reported to be the "Maine line", but specificity is pretty hard to come by. I do know they were project birds and had been outcrossed to a White just the generation before. So, that pretty much catches y'up and that's about all I know.