Hi Chip- We used to keep our boat at Pax River and I once tried to follow where the line went on the base. There is some rail still present in pavement near the warehouses towards the west end of the base, but everything else has been pretty much obliterated. There is a picture of the base's Army 060T in the lobby of the base exchange. At Dhalgren, it looks as though the rail was removed more recently and is easier to see where it went. They recently got rid of a 12" Army railroad gun that sat on a short piece of track near the waterfront. It went to the museum at Fort Eustis or maybe Fort Lee? I'm not sure which. I think that line came off of the line to the coal fired plant upriver from Dahlgren, but I suspect that you already know all of that.
A lot of military lines have been abandoned or reduced in scope. When I worked for PBQ&D in the '90's, we had a contract to rebuild the railroad on 55 Army bases.We rebuilt Fort Campbell, Sunny Point, Bayonne Army terminal, Oakland, Fort Drum and Fort Carson and some others that I've forgotten. Unfortunately, both Oakland and Bayonne were since abandoned and the rails removed. Bayonne had brand new 115# rail and turnouts! Oh well, that's progress I guess. Hope this helps a little. Ned .