It has always been isolated. When they got new engines a few years back they were barged over from either Alpena or Rogers City, I forget which. The engines were former U.P. end-cab switchers with a dynamic brake hump on the radiator end.
When I lived in Sault Ste Marie I often wondered why it had no outside connection, so I built a connecting railroad but it's in my basement and only 1/87 of actual size.