Any info on the Beech Nut complex in Canajoharie, NY - Model Railroader Magazine

You didn't see bridges because the deliveries and pick ups probably came from the West Shore Railroad branch line which ran parallel to the main N Y Central line, but on the south side of the Erie Canal and Mohawk River.  The trains probably delivered the cars to either Utica or Selkirk (Albany) yards where they were picked up by mainline freight trains.

The West Shore was owned by the New York Central and ran parallel to it from New Jersey to Buffalo.  Today, its most active line is on the west shore of the Hudson River from Selkirk to New Jersey at Weehawken, right across from Manhattan, I think.

BTW, the factory (what'sleft of production) is closing and moving to another community nearby (The name escapes me).