RailPro > RailPro Specific Help & Discussion
Frog Juicers compatible with RailPro?
JJ Crooke:
Thank you very much for the info. Ane's SmartFrog v5 is exactly what I would need if I can't use Tam Valley's Frog Juicers with the PWR-56. I throw the points directly by hand but Bill's Simple Switch Machine is an interesting option.
Prostreetamx:
Just returned from a train show in Costa Mesa California. There was one club layout that manually controlled all their track switches with mini slide switches built into the ground level of the track with the top of the slide switch exposed. They could move the slide switch or the points with their fingers to switch. The points and slide switch were connected with a piece of piano wire, The slide switch would change the frog polarity with no other linkage. Personally I use manually controlled bullfrog turnout controls with a built in slide switch.
Alan:
For your consideration... A subject not often discussed with frog juicers is their mode of operation. The design essence is a) allow the problem occur; b) solve the problem as quickly as possible. A better design approach is a) prevent the problem from occurring.
Frog juicers by design purposely introduce track/wheel arcing albeit a minuscule amount but an amount nonetheless. An actual short circuit (momentary excessive high amperage induced voltage drop) must occur to trigger the juicer, i.e., allow the problem to occur. For the tiniest fraction of a second there is 50,000°F plasma at the track wheel interface. Frog juicer circuity is designed to be very fast so the arc time is very short thus minimizing the damage. Additionally, frog juicers are typically placed near the frog and connected with shorter smaller wire gauges. As a result there is virtually no capacitance to the wiring which helps minimize arc current flow.
Switched frog polarity, which is arc-free under normal conditions, has the potential for the same and perhaps even more damaging problem when a loco runs a switch. In this scenario the system or district circuit breaker extinguishes the short circuit. A system breaker will trip much slower than a frog juicer can switch polarity. System power wiring is much longer and heavier gauge wire. It will have a significant capacitance. When the loco runs a switch the arc will be longer duration (breaker trip time) and more intense (wire capacitance discharge). Running a switch is operator error and so is within human control.
So it can be said that neither frog juicers nor switched frogs genuinely achieve the ideal design: a) prevent the problem from occurring. The real difference is frequency of occurrence. Frog juicers will introduce very frequent but less intense arcing. Switched frogs will introduce infrequent but intense arcing.
It all boils down to a single question - How good are your operators?
I am of the opinion it is better to not deliberately design in a problem. Hence why I am not a fan of frog juicers. They are convenient, easy to install, virtually plug-n-play. These attributes have value. But over the long haul the layout could aptly be named Sparky! Good operators can run a switched frog layout without arcing. Or at the very least, an absolute minimum number of occurrences.
If you are as anal about preventing arcing as I am there is a solution. Switched frogs with "wrong-way sensing". This is the path I have taken. The frog polarity is controlled by the switch motor. IR sensors on the through and diverging routes sense presence of equipment. If the switch is thrown reverse of a sensed occupancy the frog polarity to the switch machine is reversed for the duration of the sensed occupancy. The to-the-switch-machine part is important. The switch machine does not attempt to align the point rails to accommodate the wrong way approaching equipment. The switch machine is too slow for that to be viable. The operator is still going to run the switch. The only difference is the frog will be the correct polarity and no arcing occurs. Once both route sensors report the switch is clear the frog returns to the polarity dictated by points position.
JJ Crooke:
Hi everyone,
I had the chance to go down in my basement to work on my layout this past weekend for the first time in several months so I'd like to give a quick update on Tam Valley's Frog Juicers compatibility with RailPro. I was able to install an LM-2S decoder in one of my locomotive and the verdict is...
Tam Valley's Frog Juicers are NOT compatible with RailPro's PWR-56. The locomotive can run fine in one of the turnout's alignment but will create a short on the alternate alignment. The Frog Juicers will not change the polarity of the frog as it can't detect the short.
Oh well... I'll have to sell my Frog Juicers and look at the other options listed in this thread. :-\
KPack:
Thanks for the info Joel. Now we know for certain that they will not work, which is useful knowledge to all of us.
-Kevin
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