What are the design and mechanical differences of the GSC and Adirondack trucks? I have seen both types and cannot tell the difference.
The differences are to my recollection, mostly cosmetic. First, you can tell
them apart by the logo cast into the sideframe.
The Adirondack trucks would have a stylized AD logo and the GSC trucks
have the letter G located within the outline of a shield.
Other than that, they are mechanically interchangeable between locos.
Adirondack, which was located right near the D&H Colonie Shop, went
out of business a long time ago. For that matter, I think GSC did, too.