Listening to the scanner I haerd the detector near Cobleskill giving its mile post at 301. Where does the zero milage start on the D&H? In PA or at the canadian border? I allways thought that traffic would be east or west bound on that line but they are called north and southbound.
Are you sure you were hearing this on the D&H frequency?
I ask because of two issues:
1) There aren't any detectors on the D&H near Cobleskill. At least not ones that you can hear in town, typically.
2) The milepost location is out of whack. The nearest detectors are at MP 528 (Brooker Hollow Road, between East Worcester and West Richmondville) and MP 503 (NY Route 30, Esperance station). Cobleskill's MP is somewhere around 517.
Mileposts on the D&H were renumbered during the dark ages of Guilford ownership, based on MP 0 at the east end of the Maine Central, near Mattawamkeag, Maine. Thus, MP 301 would be on the B&M in eastern/central Massachusetts somewhere.
Possible explanations:
A) what you heard was a D&H axle count (possible, but odd numbers of axles are relatively unusual) I suppose an intermodal train with some of those weird articulated well cars might be an odd number.
B) You picked up a Guilford detector on a skip (unlikely again--Guilford's dispatcher line is super strong, easily picked up in Coby when the atmosphere's just right, but a detector transmission that far would be seriously weird)
C) It was a CSX detector (again unlikely, MP 301 on CSXs Water Level Route would be a bit west of Syracuse)
Anybody have other ideas?