As I posted earlier, I remember the Rutland frt going thru Rensselaer (from Troy to the B&A main) in the mid-50's. I also remember, my father (an NYC man) calling it the "Rutland Milk Train" to Chatham.
I believe the B&M tracks into Troy were gone by '62-'63 maybe '65 at the latest. Also the Green Island bridge lost it tracks from Troy to Waterviliet (across the Hudson River) around '65, and the bridge was made all auto traffic (the bridge fell into the Hudson in 1977).
As for the PC "parting the weeds" near the old station, I don't think that happened (I'm an old PCRR Conductor/brakeman), the farthest I ever went into Troy, was the old NYC frt yard in mid Troy (just north of where the old main came from the old station)...we spotted a few industrial tracks/grain. The D&H also had trackage rights (and still does with CSX) to spot grain cars there.
CR abolished the Troy Switcher in '77 or '78, and those old guys "bumped" down to the Depot Switcher (Rensselaer Station), I know this account I was one of the guys bumped! And it took a few years before I could hold the Depot Switcher again.