Wasn't that already done awhile ago? Or is this a new connection?
You may be thinking of the Trashmania -> Fenris rail.
I had plans to connect mine for a while, but I finished it last night.
So currently you can get to:
Town
BF's Domes (above water, you can see them but not reach them)
The Meadow (or where the revenant bastion's swastika was obliterated)
Auxiliary A (some random stop just past a wooden shack I found, it seems abandoned)
Northlands (where my northern death factory is)
Fenris (view of the open side)
Shade's rail (connects to the stop just after the fenris stop if you're heading north)
I'm open to suggestions for other destinations. I intend to extend my rail westward as far as I can. No real reason, just doing it to have an easily accessible place far away from the clutter near town and the northern town on shade's rail.