Hey, without pics it's going to be difficult to describe..But here goes: "" In this discussion, for clarity purposes we'll call the single end of a switch (T.O) "entry" and 2 diverging tracks "exit" or "exits"... On MRR I have an older code 83 power routing curved Shinohara switch..This is gapped at 4 exit rails. It has worked fine while employing it as to have a run around in main line. The 2 tracks converged after about 6 feet at an all-live atlas TO..Past this is TO for switchback were trains pass it , throw TO and Train reverses and continues climb up grade...Past THIS T.O. is tail of switchback..Back in main before SB TO is an Atlas T.O to engine house and a couple holding yard tracks...As I wished to have a turning wye, I took inside 83 flex out of rail joiners at at opposite end from Shinohara curved and merely bent it around in other direction to form a 21" radius curve past rear of Engine house and connected to first yard track it hits, added an Atlas RH T.O. here and connected new curve to it .. Its 'entry' rails form the tail of the new turning wye, one 'exit' now recieves new curve, other is in the yard track out to switchback...So, this wye is within the switchback trackage and so we are dealing with a 'tail' within a 'tail'..Every permutation of aligator clipped jumper wires across Shino gapped 'exits' or removed jumper from , one set inside, outside; took them off , hooked them to SB tail from parelleling main line ( as gaps at Shino leaves whole area isolated due to main DCC throttle connected to main line BEFORE its entry rails...So, either I get no power in wye rails, or system shorts out !! I can't figure out the wiring problem..All T.O.s are 'all live' Atlas (isolated frog type). Only One T.O. is 'power routing' (no gapped frog),the curved Shino..... I do intend to employ a Hex Frog Juicer to do the polarity change in frogs where needed..But in past I was always able, using jumpers to emulate the final outcome of a track polarity problem, adding/removing them until I'd get the final action I'd want...This time no matter what I do, connected, unconnected no permutation works !! Again, either no current somewhere or current but eventual short out when engine crosses gaps...This makes no sense as usually Atlas all live allow most rail connections being frog is isolated from + and - until a metal wheel or pickups of loco span it..If you understand the dilemma without pics, can you tell me what I am not comprehending circuitrywise..? I just can not set up a test pattern, say..Gapped ,not gapped, this yes, this no so as to be able to manipulate jumpers to act as switches to get loco through the turning turning trackage and heading toward SB tail in a new direction...!! What am I missing ? One tiny aspect, probably unrelated is I have a code 70 #4 Shino after an Atlas TO for 2 engine stall tracks..These 2 tracks ARE gapped thus isolated from Shino 'exits' and get their current from perminant jumpers from main line near by...
If I am following you correctly, you have a turning wye with two all-live turnouts and one power-routing turnout, with both legs of the power-routing turnout double gapped. You say that when you apply power to the isolated section, you get a short when the engine crosses the gaps. Do you get a short on both sets of gaps and are you making sure the turnout is aligned for the leg with the gap you are crossing? Everything beyond the gaps is a reversing section. With power applied to that section, you should be able to cross one of the gaps but get a short at the other one(again, the turnout has to be aligned for the correct leg when you cross the working gap or you will get a short regardless). If you flip the phase(polarity) of the reversing section, you should be able to cross the other gap, but will get a short if you cross the one you could cross before.
Robert, firstly, thanks for even reading my long dillema and responding..If I get YOUR question right, I am running loco from 'entry' of Shino and have points toward left hand exit, beginning leg of wye..so I believe that answers you as to where I am (Loco position)..So, as I also wish to keep power to rails which connect to RH Shino exit (gapped), outside of wye, current ,of course needs come up to THESE gaps for other loco activity in layout..If I kill THIS current wye might work , but rest of RR is dead...So, loco goes into power routing T.O.'s left 'exit' onto first leg (new curve born out of old passing track flex which parelleled main)..It will keep going but will short if I connect next T.O., I.E. the RH Atlas who's 'entrance' is the wye's tail (or wize tale, huh ? ). I don't connect it with rail joiners yet..I use the gator clips across rail ends leaving THIS switch 'floating' but under juice as if joined. This is precisely why I use gator clips; so as to manipulate in various ways to obtain desired results and to see physical logic needed..Last night I got loco to run onto first leg..I put a diesel on 'floating' tail and she revered up..But, with tape isolating its exit rails(as if gapped), soon as diesels wheels hit rails of first curve that first loco is occupying near past Shino, it shorts ! This is BTW is an Atlas (isolated frog)..So, this tells me polarity from 2nd leg (into Atlas's 'normal' straight exit (RH #8 T.O.) via gators need fliping somehow.. So I flip it with gators in a new configuration which, say allows both engines to roll..But, now 1st loco, if backed up toward Shino 'entry' rails will short, passing old gaps it passed a minute ago. 'Entry' rails here, of course are the main line ..!! Robert , I know Hex Frog Juicer takes care of the age old polarity problem of reversing loops..But I was led to believe with HFJuicer we need only connect it correctly on one end and then single leads go to a frog or frogs , that no gapping or other wiring is needed..I can not see how a set up like mine will ever operate WITHOUT gapping something...It's the exit and entry rails all around which I can't employ gators to simulate even the flipping poles the HFJ would DO !! In fact the 2 or 3 Atlas frogs don't even seem to have bearing on problem..It's the stock rails of Atlas and/or points of Shino which I just can not set up even a temporary circuit as I/we have been able to in years past...It's like I've discovered the only track arangement that we never can have.. But, maybe you will spot something now...Thanks again, Mark
No, this is what I was trying to make clear in your Hex Frog Juicer thread - with a reversing section you have to have it isolated at BOTH ends and have something to reverse the phase of that section.
You pick a side, or the tail, of the wye, and you ensure that is fed by itself, but only via the reversing unit's outputs. The tail ends, probably, on its own, so it doesn't need a gap there. However, if you are reversing one of the two sides of this 'triangle', you must make sure there is a gap just before the turnouts at either end. If you are going to run metal trucks and wheels with pickups to lighting in passenger cars, and your train is going to be sometimes longer than the distance between the gapped ends of the reversable side, you must cut a second set of gaps at each end. The gaps at each end, two pairs each, must be just a bit farther apart than the longest wheelbase likely to pass over them with metal wheels. IOW, imagine you have a limited passenger train with seven heavyweight cars of various descriptions trailing the loco and tender. The loco will trigger the reverser as soon as one of its metal tires bridges the gap. That's good. Or, it'll do that at the other end of the reversed section if the gap just crossed is not conflicted already. Now, with the engine crossing the conflicted gap at the far end, or just crossing the gap that is not conflicted at the far end, the metal tires at the end of the consist might be covering the ends of both rails at the first set of gaps crossed. If those gaps are separated by more than the length of the truck in which they ride, there'll be no short because that bit of rails is dead. This is explained in the DCC Specialties PSX-AR manual, but even if you are using another brand of reverser, or another type, the physics works the same.
ALL you guys above,,I have become Homer Simpson regarding MRR matters..D O H !! For some jelly donut reason I got stuck in my pea brain that the Hex FROG Juicer is named that because all we need to do is to connect it to frogs !! Well , I went down to the local pond and caught some bull frogs but it still didn't work ! DOH ! Actually, all seriousness aside, I took several of you through long drawn out paragraphs , yours and mine, believing this about the Juicer...Of course this was wrong !..I do savvy now...Simpsonly put: Reversing sections of all types MUST employ gapped sections where necessary and then FROG will instantly change to correct polarity for each frog either before or after gapped section of rail if not already matched correctly...My track configuration of a wye within a switchback is no different than any other reversing section..I only have to figure out which leg, legs need gapping , THEN hook up auto reversing unit to handle frogs..We now just throw switches (T.O.s). One final question: Is it the fact that motors in DCC are running on AC, that sections gapped from one another may be: +- and - + ; that motor remains same direction/speed in alternating current when new polarity is under wheels ? Or is it that motor still DC , and so frog must now match rails before itself and /or after itself ? And then, what , digital commands/packets/CV values (I think) are AC ? Thanks again to all above for your energy exerted over my DOH moments; especially those who (correctly)stated the need for gapping.
The motors are still DC. The DCC power is square wave AC(that's why I refer to phase instead of polarity, an AC voltage is constantly changing polarity). The decoder rectifies the AC into DC to drive the decoder circuitry and to power the motor.
Yes, but rails then ARE AC from power source.. I know AC flips poles..I guess it's 60 hertz/sec. No ? Why early on Lionel started the 3 rail system.....I think AC Gilbert, American Flyer was AC also. But you could not have a reverse loop in 2 rail AC without the usual wiring and toggle switches needed..
In DCC the rails carry the DCC commands and power as an AC digital signal at approx. 8000 hertz. Unlike DC, where the polarity on the rails determines the direction of travel, the instantaneous polarity of the DCC signal makes no difference to the decoder. It dutifully rectifies this 8000 Hz "AC" signal to provide power while simultaneously extracting speed, direction and other operational information from the incoming stream. The proper voltages are then applied by the decoder to motor, lights, sound generators etc. However, just like DC, when the track configuration is such that the right rail loops around and bumps into the left rail, you get a short, thus the need to provide isolated reversing sections and flip the polarity/phase of the track power so that the approach trackage and the reversing section trackage match polarity at all instants. Unlike DC,with DCC this flipping can take place right beneath the locomotive without affecting its operation. Simple rocket surgery.
Holy cow! Well, the "devil's advocate" must reply with...investigate getting rid of all wiring problems and install r/c with onboard batteries in the locos. Then you won't need frog juicers, wires, schematics, diagrams, or headache medicine. Life is way too short to look for shorts, unless you left them somewhere. Woodie
Woodie , I posted very same thought a while back..Have a 'refueling track' in engine yard which IS electrified..Engines roll onto it and recharge batteries as if really fueling up ! Yeah, as much DCC is the latest and greatest, in future I'll bet it will finally go all battery and transponders only for commands ..Tracks essentially cold like 1:1 scale (though they do use tracks for return in other electric devices along tracks..We'd do same..Or, do wiring under layout, but ONLY for this..
