To bring this back to Cape Vincent...
I haven't been to the Marina in maybe 8 years (and that was just to check out the station); there were no locomotives there then. A friend, Brian Wood, lived there for several years. He was back up a couple of weeks ago and checked out the area. Here's what he found:
Marina 5.JPG (41.73 KiB) Viewed 4131 times
A pair of ex- US Army (USAX) 12 ton Plymouths. More of his shots here:
http://s1215.photobucket.com/albums/cc5 ... 0critters/
I also found this online:
http://www.rrpicturearchives.net/showPi ... id=1745019
No idea whose they are, where they came from, or how they wound up where they are.
(If you look at the Marina in either Google Earth or Bing Maps, the units are west of the station, next to the large storage building. Brian couldn't tell if they were on rails, or just sitting on the ground.)