Blair & Rasa
Yes, this is true- most AC consumer products do NOT fare well on DC.
Effectively, Digitrax, and perhaps others, appear to have "built in"
protection against DC reversal, a common source of damage for many other
product lines; for example, when you go out and buy a replacement 3rd party
wall wart that has -9V on the center of the connector, instead of +9V, and
your precious calculator calculates it's last. Anyway, the built in
protection of a bridge rectifier is nice, but it "costs" you in terms of
voltage overhead. When users complain of their DCS100 units overheating,
that rectifier is one (but only one) of the contributors to that
We're on the same wavelength, as I'm EE technologist. I asked my question
intending to get feedback on operational satisfaction at 12VDC input from
people who would be cognizant of the issues, not to find out about DCC
system inputs - but I'm sure this is all interesting to others, as well.
And your explanation is, as usual, succinct.