W
ith modern Digital Command Control has come
two very useful methods for reducing intermittent
power feed issues with our locomotives: frog juic-
ers and keep-alive supercapacitors.
Back in the early days of DCC, those experimenting with the
technology realized they could build a circuit to detect a short
in the track and swap the polarity in the rails in mere micro-
seconds, well before the short actually affected loco behavior.
The result? Now reversing loops and wyes could automati-
cally detect a polarity mis-alignment in the rails and elec-
tronically flip the polarity to eliminate any short, with no
mechanical Rube-Goldberg devices needed.
Duncan McCree of TAM Valley Depot took this concept even
further when he applied this auto-reversing approach to
swapping turnout frog polarity. No longer did you need to
wire separate mechanical contacts somewhere to flip frog
polarity. You could just have a smart reversing circuit do it all
electronically with no moving parts!
Thanks to a frog juicer, you can now power any frog simply by
running a single wire to that frog from the frog juicer board
and it would take care of the rest. Instead of dead frogs you
Publisher’s Musings - 1
Publisher’s Musings
by Joe Fugate
Frog juicers or keep-alive?
Reducing intermittent power feed
issues with our locomotives
MRH-Dec 2014
