Without desiring it, I also have had a LOT of experience with this
issue. Although alcohol or lacquer thinner can remove a light
infestation, most of the time a wire brush is needed. The foam rot
does remove the truck side frame blackening, but in my experience it
has not significantly pitted or destroyed the Zamac. However, it can
and does attack the brass on the wheels, leaving corrosive pits.
Unlike others reporting Zamac rot in their CV trucks, I have not yet
had that experience (I probably have in excess of about 100 of them,
probably at least half for 35-50 years) except for a single crumbled
equalizer bar on a passenger truck. My ongoing program of routinely
replacing older wheels sets with new Reboxx wheels as cars are set on
the track reinforces my view on the matter (the trucks get pretty
well-handled in this manouver). Now, Silver Streak and Varney trucks-
that is another matter.
It has always been my impression that George Hook (CV's founder)
maintained very high standards in his casting work.
Without any scientific knowledge on this matter whatsoever, my last
impression is that if zinc rot has not set in by now, it probably