Sometime back in the Nineteen-Sixties there was a cartoon in Railroad Model Craftsman which showed a railfan/modeler surrounded by model trains et cetera, opening his basement freezer and explaining to a guest that part of the hobby was collecting things, and that here was an icicle which had once hung from the roof of the somewhere-or-other depot.

Significant Other, who firmly believes that preserving any of this (except possibly which ever PV she may be a guest aboard) is more than a little bit odd, perused this thread and then expressed the thought that a photographer who was dressed in the style of days past photographing a relic with equipment which was itself a relic was somewhat touching. (Perhaps she actually said 'touched'.) She then submitted her own nomination for oddest preserved artifact, to wit - yours truly.

GME
(Who is certainly nowhere near in the running for 'Oldest Preserved Railroad Artifact')

The B&O Railroad Museum has a railroad-lettered trailer on a flatcar. Even though The Museum is no longer affiliated with CSX, I think the trailer can still be considered to be on home turf.

Bear Creek Junction RR in NC sold little jars full of clinkers from the firebox in the gift shop back in the 1970's.

dave

According to "Railroad Magazine" about 1960, the term for an American Southern states logging railroad that used its own product for its rails was "pole railroad". The steam locomotive wheels were grooved. "Carload Andy" Osspring's descendent "Frog" Smith was the author, and he found 2 of these logging locos abandoned in the South woods. I hope I have the names and relationships right , but it should be something to help you search your old issues.