Where does this piece go on my Scaletrains SD40-2?

[NCC42768]

Got a Conrail Q one from the latest batch---the rear-most wheelset was way out of gauge, and fixed it, but in doing so, knocked this little bit off---it's likely from around the rear truck, but I can't find anywhere that looks like a piece used to be glued there but is now missing.

[NCC42768]

Possibly answering my own question, after looking at tons of Conrail and SD40-2 pics:

I think it's a breather/vent pipe for the fuel tank, and it actually attaches to the conductor's side sight-glass mount:


I couldn't find a pic showing exactly this length/position on a CR SD40-2, but did find a CR GP38-2 and an NS SD40-2 that seemed to match. And the notch in the bracket fits around the sight glass mount perfectly.

There's no glue residue at all, I think it was basically "just sitting there" until I took it out of the clamshell.