PSX-AR no gaps needed?

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?

How about a drawing?

Rich

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

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.

My sentiments exactly. Without gapping and isolating the reversing section, it sees that a dead short is inevitable.

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.

Rich

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

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?

Richard

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.

That is not exactly correct. While the frog is isolated on a Peco Insulfrog, jumpers connect all of the turnout rail segments before and after the frog. There are no gaps on an Insulfrog except to isolate the frog itself.

Rich

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.

Rich

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 a

Interesting. No I was talking about the new track. I still have all the other gaps there. Indidcated in the diagram.

I only see two sets of gaps in that diagram which means that the reversing section is not completely isolated.

Rich

Power routing and gaps are not the same thing. Yes, the Insulfrog is power routing. Power is not provided to the closure rails and frog rails directly from the point rails. Rather, the point rails pick up power from the stock rails. Thus, power routing.

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.

Rich

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

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 t

I think he said he is though.

Richard