OK I'm confused here. I have the PSX-AR. I just recently installed new track for my reversing section. And I have not cut the gaps yet, or wired up the drop feeders to this section either.
I powered up my system today expecting a short. Nope, everything works fine. I'm like huh? So then I run a loco through the reversing section, still no short! What? And when the loco gets past the frogs on the switch. The PSX-AR reverses the polarity.
My switches are Peco insulfrogs. Is there an explination why this works. I thought I needed gaps?
Michael
CEO- Mile-HI-RailroadPrototype: D&RGW Moffat Line 1989
How about a drawing?
Rich
Alton Junction
The PECO is power routing. I like those turnouts.
Richard
Yes, because they are power-routing, when you have it thrown for the straight route to enter the loop, the diverging side is 'gapped' because it is electrically isolating the power from flowing through that side. After the train is in the loop and you throw the switch to the diverging side so the train can exit the loop, it disconnects the straight side and connects the diverging side. It's at that point the PSX is reversing the loop track, because the short occurs the instant the points conact the opposite stock rail. In fact, you should be able to get the PSX to flip every time you throw the switch, with no train on the track.
For long term reliability, I'd feed power on all 3 legs of the turnout and gap the rails beyond that for the loop. Same thing I did with Atlas, with power coming in on all possible legs, that left very little electrical conductivity up to the pivot points or other bits of stamped metal that isn't soldered or welded together. Works with Atlas and Insulfrog, won't work with Electrofrog.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Aha, very interesting!! Thanks for the explination Randy.
Yes I will still cut the gaps and add feeders.
I made a drawing of the reversing loop described in this post and i'm having a hard time understanding how the AR is working since there is always a dead short if there are no gaps in the reversing section. Even if the AR is reversing the polarity in the loop, there will still be a short circuit condition there that the AR cannot correct.
retsignalmtr I made a drawing of the reversing loop described in this post and i'm having a hard time understanding how the AR is working since there is always a dead short if there are no gaps in the reversing section. Even if the AR is reversing the polarity in the loop, there will still be a short circuit condition there that the AR cannot correct.
I have talked one-on-one to Michael about this issue, and I have encouraged him to post a diagram. Something does not add up here.
In this case, because the Peco Insulfrogs are power routing, a dead short will not occur as long as the points are thrown on both turnouts away from the reversing section and as long as there are no feeders within the reversing section. But as soon as the points are thrown, facing the reversing section, a dead short will occur. The only way to effectively operate a reversing section is to completely gap and isolate the reversing section.
I'm assuming a simple balloon loop here - ONE turnout, looped back on itself. With a power routing turnout, one side will always be gapped. The AR can switch the polarity to match whichever side is not gapped. This also assumes the power routing connection within the turnout operates as a break before make contact, so only one side is ever connected at a time.
Not quite a simple balloon loop. Here's the diagram.
The red track is the new track I recently replaced. With no gaps right now.
YOu need both rails to flow current to cause a complete dead short. REcall how we used to use common rail wiring in the DC days?
I used a balloon loop as the example to diagnose the problem. No matter what the position the switch is in there will always be a dead short circuit condition. It will take me a little while to look at the posters diagram.
rrinker I'm assuming a simple balloon loop here - ONE turnout, looped back on itself. With a power routing turnout, one side will always be gapped. The AR can switch the polarity to match whichever side is not gapped. This also assumes the power routing connection within the turnout operates as a break before make contact, so only one side is ever connected at a time. --Randy
The problem with Michael's layout is that the reversing section is not completely gapped. When the two sections of track between the divergent ends of those two turnouts are joined (where he drew that red line), a dead short occurs. To avoid a dead short, gaps need to be placed at that track joint. That would complete the isolation of the reversing section.
I guess it depends on which ones you are talking about. If there are jumpers connecting everything underneath, then it is like an Atlas Custom Line and CANNOT power route - which appears to be the case for the Code 75 and Code 100 ones. The Code 83 Insulfrogs are NOT wired like that, says right int he instruction sheet that only the way the points are lined gets power, unless you provide additional feeders. So there IS a gap within the turnout, which is always in the path against the point position.
Without gaps there certainly will be places a train cannot go without causing a short - there are a lot pof things connected to the 'reversing section' per the track diagram, not just the end of the loop part. And NO other gaps? You mean you closed up the other gaps shown on the diagram, not just the one that would be replaced by the new track? Or are those other gaps still there? If the other gaps on the left are still there, then the power routing in the turnout on the new track on the right makes the second gap. It all depends on which way the points are lined. It's NOT going to work long term without the gaps, but for specific use cases, it should work fine without the extra gap. Soon as you try a different route, not going to work, it will encounter a short that can't be fixed by the PSX because to fix it in one location, it need to be AB, and to fix it in the swecond location simultaneously connected because of the lack of gaps, it needs to be BA. Then it will just shut off totally, acting as a breaker.
If the right most turnout, the one feeding that new piece of track, the one just out of the picture to the bottom, is set for the train to go to the right around that side of the wye, it should work fine, no reversing is even needed there - trace around the layout, if the outside rail is the red side, it's the red side all the way around, just a loop with a jog in it. However, if the switch is lined to direct the train to the left, onto the new track, and there are truly no other gaps - it should short as soon as a train crosses the gaps on the left side, because it is impossible to match polarity.
Interesting. No I was talking about the new track. I still have all the other gaps there. Indidcated in the diagram.
Motley Interesting. No I was talking about the new track. I still have all the other gaps there. Indidcated in the diagram.
rrinker I guess it depends on which ones you are talking about. If there are jumpers connecting everything underneath, then it is like an Atlas Custom Line and CANNOT power route - which appears to be the case for the Code 75 and Code 100 ones. The Code 83 Insulfrogs are NOT wired like that, says right int he instruction sheet that only the way the points are lined gets power, unless you provide additional feeders. So there IS a gap within the turnout, which is always in the path against the point position.
But the point rails, closure rails, and frog rails are joined together by jumpers. There are no gaps. Just do a continuity test on an Insulfrog. So, when power is routed to the point rail from the stock rail, power is also present on the closure rail and the frog rail. Just look at the Insulfrog. The only gaps that you see are the ones isolating the frog.
But it IS, electrically. If you feed just the point end of the turnout, and have no feeders beyond the frog, aand you put two sections of track after the frog, one on each route - and you set the points to teh straight route and have no power on the diverging track- it IS like there is a gap. Phyical gap or electrical 'switch' built in to the points, same difference. If the power is removed from the track when the points are directed away from that gap, it's an open circuit. Same as a gap.
Same as putting insulated joiners on the siding and putting a toggle switch in the feeder line that connects past the insulated joiner - open the switch to kill power to the track, you are in effect 'gapping' the electricity.
And if in the situation laid out above, if the trains move on BOTH legs regardless of the point position, then it's not a power routing turnout. If I put an Atlas Custom Line in a setup like that, witht he only power feed being the point end, locos on either route would move regardless of how I lined the points - or even if I held them smack in the middle, not lined to either route. Because they have jumpers underneath that connect the closure rail to the rail beyond the frog.
Randy, I think that we both agree how the Peco Insulfrog operates. We just differ on terminology. You call the movement of the point rail away from the stock rail as a "gap". To me, that is simply "power routing". If the point rail is not in contact with the adjacent stock rail, then the point rail remains unpowered.
That's why an unpowered stub siding remains so, as long as the point rails are set for the straight through route. Only the divergent stock rail side of the stub side is carrying power. However, add a pair of feeders to the stub end of the siding and the power routing feature is defeated. Now, flip the feeders on the stub end of the siding, and you create the makings of a dead short as soon as the point rails are thrown to the divergent route.
That is essentially what is happening in a reverse loop. Power feeds on the tail end of the turnout carry power around the loop and back to the divergent end of the turnout even with the point rails set to the straight through route. But the polarities are mismatched as the track folds back onto itself. So, as soon as the point rails are thrown to the divergent route, a dead short occurs.
That is the situation on Michael's layout. As long as the point rails on those turnouts are set to avoid that reversing section (the red line), the layout will operate without a short. But, throw the point rails on those two turnouts to set the route through the reversing section, and a dead short will occur.
The only way to avoid that dead short is to add gaps to completely isolate the reversing section. On Michael's diagram, he only shows two sets of gaps. That is insufficient. The reversing section is not completely isolated. A loco trying to run through that reversing short will come to a halt as a result of a dead short. If a loco is running through that particular reversing section, then there are gaps that are being overlooked and not shown on the diagram.
That is why I don't like to refer to the Peco Insulfrog as "gapped". And that is at the heart of Michael's question. How can I run a loco through a reversing section without gaps. The answer is, you cannot.
richhotrainThat is why I don't like to refer to the Peco Insulfrog as "gapped". And that is at the heart of Michael's question. How can I run a loco through a reversing section without gaps. The answer is, you cannot.
richhotrainRich
I think he said he is though.
And therein lies the mystery.
When you look at that track diagram and the location of the gaps, how can a loco run through that reversing section marked by a red line?
Does anyone following this thread believe that can happen?
he's got what looks to be a couple of reversing loops piled on top of each other. Are we talking about the loop that goes "down", or the one that goes "left"?
-Dan
Builder of Bowser steam! Railimages Site
There is only one reversing section, and it is marked with a red line.
richhotrain And therein lies the mystery. When you look at that track diagram and the location of the gaps, how can a loco run through that reversing section marked by a red line? Does anyone following this thread believe that can happen? Rich
It's pulsed DC and the decoder determines direction, the need for gaping is to ensure that there is no direct short or no shorts are caused by the wheels, the PECO switch accomplishes that for one side of the current. YOu need both sides/rails to have current flow. In this case you only have one since the switch acts as a gap and power router.
richhotrain There is only one reversing section, and it is marked with a red line. Rich
And there's that wye immediately next to it, and the loop going the other way ... or was there a description (or other pic maybe?) that negates those two?
Train Modeler richhotrain And therein lies the mystery. When you look at that track diagram and the location of the gaps, how can a loco run through that reversing section marked by a red line? Does anyone following this thread believe that can happen? Rich It's pulsed DC and the decoder determines direction, the need for gaping is to ensure that there is no direct short or no shorts are caused by the wheels, the PECO switch accomplishes that for one side of the current. YOu need both sides/rails to have current flow. In this case you only have one since the switch acts as a gap and power router. Richard
Let me take one more shot at this before I walk away from this thread completely dazed and confused.
I drew a crude track diagram showing how this reversing section is set up according to Michael.
The polarities are shown using red and blue for the respective rails.
The gaps are marked by black dots,
The four controlling turnouts are marked A, B, C, D.
When the points are thrown on turnouts B and D to route a loco thru the reversing section from B to D or D to B, current is flowing across both rails between B and D.
I see no way that the loco pass through the reversing section, since a dead short will occur where mismatched polarities meet.
Throw the turnout at D, the polarities will mismatch, instant short, the AR will flip everything from D back to the gaps on the left. Now the polarity mismatch will be at the gaps at the left, but that's OK, we're already past there.
It's NOT right, because the AR is more or less acting as just more track feeds, not a properly isolated reverser. But it should work. The key is the reversing taking place when the switch at D is lined, NOT when a loco crosses gaps.
Going the other way, no way can it work, unless the turnout at D is switched after the train passes. So without proper gaps, running A-B-D-A will not work, but running A-D-B-A should. A-D-C and C-D-A is no problem, that's just the outside of a large loop. Same with A-B-C.
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A-B-C, C-B-A, A-D-C, and C-D-C all will work because of the Insulfrog's power routing feature. Power routing prevents a dead short from occurring between B and D on these four routes because there is a "dead" rail in each instance at the B-D connection.
A-B-D-A and A-D-B-A will not work because of a dead short in each instance as four "live" rails connect together with mismatched polarities.
However, cut gaps in the rails where they meet between B and D, and you can run locos in those two directions as well without a dead short because now you have completely isolated the reversing section.
Power routing has nothing to do with why the simple around the big loop paths work. There simply is no short under any circumstances if you go around the long way via D and C, or take the shortcut at A.
By rights, if the turnout D is lines towards C, the rails extending to the left before the gap that should be but isn't there should be black, NEITHER polarity, because the power is cut off. Line it the other way, towards B, instant short - HOWEVER, the track from D to the gaps on the left is connected to the AR, so it can flip, now the polarity across the palce where the gaps should be matches and the train can run. That's why it 'works', though you'd think it can't possibly without the extra gaps.
However - while it appears to work, you are feeding track power from the main into the output of the AR by doing this and that's probably not a good thing. It DOES need the gaps to be completely correct, however it's not a super mystery on how it works despite not having the 'required' gaps. If D were at Atlas turnout, it would fail as soon as something with metal wheels crossed the gaps on the left. As it should if a train tries to cross those gaps while D is lined towards B. The power routing capability allows you to cheat, but only for certain possible route combinations, others will never work without proer gaps.
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