You aren't getting shorts, not on an Atlas turnout. You are getting no power. The more polish and paint you put on, the worse you are making it. The frog in an Atlas #4 or #6 is completely insulated fromt he rest of the turnout, there is no location where metal parts of opposite polarity are close enough to be touched by the same wheel.
A Frog Juicer would work. The easiest way to attach a wire to the Atlas frogs (they don;t really take solder) is to use a brass screw in the hole provided. You used to be able to order the brass bars and bolts that came with the Snap Relays as a seperate item, I'm not sure if that is still available from Atlas.
Depending on what you are using to power the points, you can use contacts on the switch motor instead of the juicer.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Sir, hopefully your still out there. I have 14 Atlas #4 & 6 insulated frog turnouts that drive me nuts with shorts, I run DCC. My shifters, short base and med base stall. I've used paint and clear nail polish to work the issue (pain). Can I still use frog juicers to stop this problem or the atlas swith machince to fix it. Thank you in advance.
Dave
I guess the gators ate all the frogs. Gator, defies the laws of conservation of matter:
the more you chew it, the more there is.
Henry
COB Potomac & Northern
Shenandoah Valley
Yeo Brother, and I'm from Florida!
B. Bryce"Insul"... "Electro"... "Uni"... Just where did the term "FROG" come from for this?
Clearly you didn't grow up in the South. You should try them, they really do taste like chicken.
Squint your eyes and you can see a resemblance to the turnout
"Insul"... "Electro"... "Uni"... Just where did the term "FROG" come from for this?
Turnout Problems with Diesel vs Steam Engines(from another forum, but an interesting problem/subject)
YoHo I'm really a bit surprised that a diesel, unless it's a small switcher type is more prone to stalling than a steamer. Also, my experience is that cutting out and sound resetting on switches is BY FAR more likely to be a short condition than a dead track problem. like 9 times out of 10, If an engine traverses a switch, cuts out and starts up again, there's a short, not a dead spot. I don't know that that is the case with yours and since you aren't having issues with your steamers, it's a dead issue, but my experience says, don't blame dirt or bad pickup.
I'm really a bit surprised that a diesel, unless it's a small switcher type is more prone to stalling than a steamer.
Also, my experience is that cutting out and sound resetting on switches is BY FAR more likely to be a short condition than a dead track problem.
like 9 times out of 10, If an engine traverses a switch, cuts out and starts up again, there's a short, not a dead spot.
I don't know that that is the case with yours and since you aren't having issues with your steamers, it's a dead issue, but my experience says, don't blame dirt or bad pickup.
Hi Yoho, Before abandoning diesels I did a thorough and extensive investigation. The first thing I noted was that only diesels displayed the problems. I tried every locomotive I had, both diesel and steam. I tried a variety of speeds. At very low speed the diesels would stall on the dead frogs. At high speed they would make it across the switch without issue. At medium-high the diesel would make it across, but the lights and sound would hesitate and reset. At low-medium speed the diesels would hesitate and reset or would stall. Only one diesel had no problems. It was a Proto 1000 RS2. It almost never had issues. All other diesels did. The above issues is why I soldered the point rails to the stock rails. That reduced the number of stalls and resets, but did not eliminate them. Also, when the diesels stalled or hesitated there was no current spikes or surges. The ammeter simply went to zero. As you are aware, this meant that there was no short. When I removed the diesels from the layout and operated steam only the problems miraculously disappeared. When I returned the diesels to the layout for operation the problems returned. My last part of the testing was to power the frog of one of the switches. That totally solved the problems and all diesels would make it over the switch without issues. So, why didn't I just power the frogs on all of my switches? Simple answer. I had 43 switches. Switch machines that power and reverse frog polarity automatically are expensive. I did not have the money for that. I also did not want to spend the time to do it. And the most important (to me) reason was that I wanted train crews to manually throw switches with ground throws. This was and remains a very important part of operation for me. I simply do not want to turn my layout into a big electrically controlled Lionel layout. Yes, that is how I think of a bunch of electrical switches. Ain't my cup of tea. So, I had my solution. That was to retire all of my diesels and go totally steam. No changes were needed for the layout and I could operate with ground throws and have zero electrical control switches. One last note. When friends brought their diesels to my layout to operate they experienced the same stalling, hesitating, and resetting problems. When the would bring a steam locomotive, no problems. OK. All of the above said, my switches are all Micro Engineering switches. My problems may well be with the ME switches. That is possible. Jim Six
Before abandoning diesels I did a thorough and extensive investigation. The first thing I noted was that only diesels displayed the problems. I tried every locomotive I had, both diesel and steam. I tried a variety of speeds. At very low speed the diesels would stall on the dead frogs. At high speed they would make it across the switch without issue. At medium-high the diesel would make it across, but the lights and sound would hesitate and reset. At low-medium speed the diesels would hesitate and reset or would stall. Only one diesel had no problems. It was a Proto 1000 RS2. It almost never had issues. All other diesels did.
The above issues is why I soldered the point rails to the stock rails. That reduced the number of stalls and resets, but did not eliminate them. Also, when the diesels stalled or hesitated there was no current spikes or surges. The ammeter simply went to zero. As you are aware, this meant that there was no short.
When I removed the diesels from the layout and operated steam only the problems miraculously disappeared. When I returned the diesels to the layout for operation the problems returned.
My last part of the testing was to power the frog of one of the switches. That totally solved the problems and all diesels would make it over the switch without issues. So, why didn't I just power the frogs on all of my switches? Simple answer. I had 43 switches. Switch machines that power and reverse frog polarity automatically are expensive. I did not have the money for that. I also did not want to spend the time to do it. And the most important (to me) reason was that I wanted train crews to manually throw switches with ground throws. This was and remains a very important part of operation for me. I simply do not want to turn my layout into a big electrically controlled Lionel layout. Yes, that is how I think of a bunch of electrical switches. Ain't my cup of tea.
So, I had my solution. That was to retire all of my diesels and go totally steam. No changes were needed for the layout and I could operate with ground throws and have zero electrical control switches.
One last note. When friends brought their diesels to my layout to operate they experienced the same stalling, hesitating, and resetting problems. When the would bring a steam locomotive, no problems.
OK. All of the above said, my switches are all Micro Engineering switches. My problems may well be with the ME switches. That is possible.
Jim Six
I'm beginning to wonder the same,...if your ME switches just might have been the problem.
I plan on using all Peco switches on my new layout, and hope to utilize mostly insulafrog ones for simplicity . In most of my reading/investigation I have seen many cases where big layouts have used these quite successfully in DCC operation with no real detrimental effects.
Perhaps their 'stock' point rail contacts are better at providing reliable power to the point rails. and with proper insulating gaps during installation the unpowered frog sections are very short.
Brian
My Layout Plan
Interesting new Plan Consideration
Brian,
Have you run some trains through those 3 ways yet? I have had to shim some guard rails on some of my pecos due to very wide flangeways/guardrail spacing. Yours look like they may have a similar problem especially - with rp 25 wheels. Try pushing a cut of cars (with a loco under power pushing them) through and see how they fare.....
One issue to be aware of here is the Peco has changed their line several times over the last 25 years and there is lots of old stock floating around. My electrofrogs (early 90s-2000s) look quite a bit different than the current versions offerd by Peco.
IMHO: The best bet is to study the basic wiring schemes for the common styles of turnouts: power routing, through powered, etc. and be able to trace the power path through each one. Then you can take what you have and check it with a meter to see what type of wiring you have and how you might want to modify it depending on your preferences.
One other comment: when you ballast and paint track, it changes things considerably in regards to electrical conductivity. You can get away with lots of sketchy power paths with unscenicked track but when you soak the track in glue and paint the gremlins come out...Power routing turnouts don't anymore, unsoldered rail sections go dead, etc...
I run small brass steam and I can tell you I need every advantage I can get to have things run well. Powered frogs, keep alives, etc. all work in tandem to keep the layout operational at slow crawl speeds.
Guy
see stuff at: the Willoughby Line Site
Well, if Peco themselves does it...
To add more confusion, they are rolling out some new products which have what they are calling Unifrog - one turnout that, depending on how you wire it, is the same as Electrofrog or the same as Insulfrog.
Brian, if you go onto the Peco website, the photo shown for the Peco Code 100 3-way turnout shows that same photo. However, there is a note attached to the photo that reads, "Please Note: Photo shows Electrofrog version".
In other words, every vendor is using the stock photo for the Peco Code 100 Insulfrog 3-way turnout which is, in fact, a photo of the Peco Code 100 Electrofrog 3-way turnout.
Go figure.
Rich
Alton Junction
How about this one that is also called an insulafrog Peco? Looks like those rails come together at the frog,...(no plastic frog) ??http://www.traintekllc.com/peco-sl-99-code-100-insulfrog-3-way-medium-radius-turnout/?gclid=EAIaIQobChMIr7vV_fWV2wIVDcZkCh0RWwGwEAQYAiABEgIJT_D_BwE
same photo here, of supposely insulafrog..http://www.hobbylinc.com/peco-code-100-medium-radius-three-way-turnout-model-train-track-ho-scale-1055?source=froogle&gclid=EAIaIQobChMIr7vV_fWV2wIVDcZkCh0RWwGwEAQYBCABEgJNaPD_BwE
CONFUSING !!
rrinker Yours are insulfrog. That one on the bottom pic is an electrofrog, not an insulfrog. --Randy
Yours are insulfrog. That one on the bottom pic is an electrofrog, not an insulfrog.
Thats what I thought as well, but the gentleman selling it swore it was insulafrog
Water Level RouteLook at the tip of the frog where the rails come together. If there is a small piece of black plastic, then they are insulfrogs. If metal, then electrofrog.
Here are two photos of my code100 Peco 3-ways, insulafrog
I do notice a difference in the rail separations at the first frog verses the second 2 frogs. Certainly looks like shorting due to wide wheels could be more of a problem at the first location than at the second one
...and BTW I did note of the comment about 'just close proximity', as opposed to direct contact, creating a shorting problem when using DCC.
This is a photo of recently advertised insulafrog Peco 3way that the EXPERIENCED owner claims has worked fine on his DCC layout or years, Close inspection shows the metal points are quite different from those of mine above. ??
Especially if you remove the spring and use a slow motion switch machine. Out of the box, the frog is powered based on contact of the point rail with the stock rail, switching automatically with the points so you need no extra switch machine contacts or Frog Juicers. But they also come with a spring which hold the points tightly against the stock rail. If you want to use slow motion switch machines, you pretty much have to take the spring out, or you don;t have any slow motion action - the points just snap into position once the slow motion machine moves far enough to overcome the spring tension. Now you have a less solid connection.
If you use a Frog Juicer, you don't have to modify anything, just hook the juicer to the frog wire, and it will power the frog, closure rails, and points from the frog side. With switch machine contacts and slow motion machines, there's a chance the contacts could switch before the points move - which would cause a short. So if you cut the jumpers to isolate the frog, this can;t happen. But now the closure rails and the points are powered only by contact of the point against the stock rail. That's where the other added jumpers come in, connecting the point and closure rails to the adjacent stock rail with a wired and soldered connection.
More bulletproof. Belt and suspenders. I'd rather do this on the workbench and then never have to worry than have a layout and after a year or two start getting erratic operation and have to rip things up to fix it.
railandsailIf the electrofrog Pecos are made for DCC operation, why should someone have to modify them?.....cut existing jumpers??
To make them better than new, or perhaps more bulletproof is a better term. Steve Otte had the best explanation, scroll down till you get to his post.
http://cs.trains.com/mrr/f/744/p/268041/3035733.aspx#3035733
rrinker Reliable turnout wiring is the same for DCC or DC. Peco Electrofrogs are easy to make bulletproof - the newer ones have gaps in the ties underneath where you need to cut existing jumpers and add new ones for absolute bulletproof reliability.
Reliable turnout wiring is the same for DCC or DC. Peco Electrofrogs are easy to make bulletproof - the newer ones have gaps in the ties underneath where you need to cut existing jumpers and add new ones for absolute bulletproof reliability.
rrinker The Peco instructions show where to change the jumpers for the ultimate in reliability. It's not difficult, but you do need to know how to solder and you need a fairly fine tip on your soldering iron to get into the space without melting ties. It's well worth the effort, especially for a slow speed switching layout, and by making this effort and having the turnouts totally reliable electrically, there's no reason to spend money and put keep alives in every loco. A properly wired Electroforg has no spots where there isn;t a rail with power touching the wheels of even the smallest loco. --Randy
The Peco instructions show where to change the jumpers for the ultimate in reliability. It's not difficult, but you do need to know how to solder and you need a fairly fine tip on your soldering iron to get into the space without melting ties. It's well worth the effort, especially for a slow speed switching layout, and by making this effort and having the turnouts totally reliable electrically, there's no reason to spend money and put keep alives in every loco. A properly wired Electroforg has no spots where there isn;t a rail with power touching the wheels of even the smallest loco.
It's what you did at the time. Most of the turnouts were Atlas, but back then Atlas only had 4, 6, and wye. No curved - you used Shinohara. No 8's, you used Shinohara. Or else you hand laid it all.
I too prefer the closure rails and point rails to always be the same polarity as the adjacent stock rails. Ironic that this is referred to as "DCC Friendly" these days. All because the DCC circuit breakers are instant acting electronic devices, while the old thermal breakers in DC packs would often not even notice the shorts - but that doesn't mean it wasn't shorting. A short is a short is a short, DC, DCC, AC, whatever.
rrinker You aren't using the Tortoise contacts to power the frog then. This was a logn time ago - more than 20 years ago, on the club I belonged to at the time, and if you used the Tortoise contacts AND things weren't lined up just right, an unmodified turnout would short if either the contacts switched before the point rail moved away from the stock rail, or if the point rail moved to the new stock rail before the contacts switched over. This was enough of a point that there were instructions all over how to modify the Tortoise by increasing the dead space between the contacts. Mechanically, there were no issues, the points held firmly in either position, rollign stock did not pick the points. But it could be rather finicky to get things centered "just so". The correct solution indeed is to modify the turnout, not the Tortoise, because there's no mechanical reason why the Tortoise should have to be so perfectly dead center. Relatively close, yes, but there is ample range of motion on the throw rod that they don't need micrometer precision in lining them up to work well. You can't have it so far off center that the wire hits the side of the hole before the throwbar has been moved all the way, but it doesn't have to be perfectly in the center of the hole, either. --Randy
You aren't using the Tortoise contacts to power the frog then. This was a logn time ago - more than 20 years ago, on the club I belonged to at the time, and if you used the Tortoise contacts AND things weren't lined up just right, an unmodified turnout would short if either the contacts switched before the point rail moved away from the stock rail, or if the point rail moved to the new stock rail before the contacts switched over.
This was enough of a point that there were instructions all over how to modify the Tortoise by increasing the dead space between the contacts.
Mechanically, there were no issues, the points held firmly in either position, rollign stock did not pick the points. But it could be rather finicky to get things centered "just so". The correct solution indeed is to modify the turnout, not the Tortoise, because there's no mechanical reason why the Tortoise should have to be so perfectly dead center. Relatively close, yes, but there is ample range of motion on the throw rod that they don't need micrometer precision in lining them up to work well. You can't have it so far off center that the wire hits the side of the hole before the throwbar has been moved all the way, but it doesn't have to be perfectly in the center of the hole, either.
??????????
So they were not using the contacts to power a truely isolated frog, they were using the contacts to guarantee the power routing?
What a bad idea.......
This is why I don't like power routing turnouts with traditional all metal frogs connected to the points/closure rails.
If the point rails and closure rails are always the same polarity as their associated stock rail, you never have these problems, and you never have shorts from the back side of a wheel.
This is again why I feel the Atlas wiring approach is best.
The completely isolated metal frog can be polarity controlled by a relay, or switch machine contacts without any such issues.
Sheldon
Old Fat Robert Guy and Other Fine People: I am not going to comment on whether or not one should or should not use insulated frogs. That is for others to comment on. However, I want do want to comment on the question of Shinohara power routing TOs and Tortoise switch machines and the "shorting" issue. I use (almost exclusively) Shinohara (not Walthers Shinohara!) code 70 track and TOs and have done so for many years and I have been using Tortoise switch machines for better than twenty years. I cannot ever recall a "short" happening from this arrangement. Never. I am not even sure how it would happen, but assuming the wire actuator rod (only way I can think of this happening) touched the rivet on the throwbar/tie and caused a short the easiest and quickest way I can see to fix would be to to slip some insulation over the actuator rod. Just my couple of shillings. Old Fat Robert
Guy and Other Fine People: I am not going to comment on whether or not one should or should not use insulated frogs. That is for others to comment on. However, I want do want to comment on the question of Shinohara power routing TOs and Tortoise switch machines and the "shorting" issue. I use (almost exclusively) Shinohara (not Walthers Shinohara!) code 70 track and TOs and have done so for many years and I have been using Tortoise switch machines for better than twenty years. I cannot ever recall a "short" happening from this arrangement. Never. I am not even sure how it would happen, but assuming the wire actuator rod (only way I can think of this happening) touched the rivet on the throwbar/tie and caused a short the easiest and quickest way I can see to fix would be to to slip some insulation over the actuator rod. Just my couple of shillings.
Old Fat Robert
Robert,
I presume that you aren't using the electrical contacts?? I was referring to the use of the Tortoise contacts to power the frog. What you are saying is correct if you are not using the tortoise contacts to power the frog. Many people use "Tortis" without using the contacts and they work as you describe - quite well..
rrinker Reliable turnout wiring is the same for DCC Older Walthers/Shinohara turnouts, the ones NOT marked "DCC Friendly" have the same problem in DC as they do in DCC, if you use a Tortoise machine to control the frog polarity, you better have it pretty darn near dead on centered, because of the contacts change before the points have moved off the stock rails, you get a short. The gap in the Tortoise contacts is very small - this issue spawned a number of "how to modify a Tortoise" articles on cutting some of the copper off the board to make the gap bigger.
Reliable turnout wiring is the same for DCC
Older Walthers/Shinohara turnouts, the ones NOT marked "DCC Friendly" have the same problem in DC as they do in DCC, if you use a Tortoise machine to control the frog polarity, you better have it pretty darn near dead on centered, because of the contacts change before the points have moved off the stock rails, you get a short. The gap in the Tortoise contacts is very small - this issue spawned a number of "how to modify a Tortoise" articles on cutting some of the copper off the board to make the gap bigger.
Randy - I totally agree with the first line.
IMHO the easier solution to the shorting issue in the second paragraph is to gap the frog and isolate it. This is easier to do before installation and does require soldering a feeder to the newly isolated frog, but I find it easier and more reliable than trying to modify tortoises. This does leave the points powered by contact to the stock rail (or by tabs - depending on the age of the TO).
As for the curved turnout discussion, I do agree that it is frustrating to try and plan trackwork without the actual switch in hand. I took a radius tool with me to buy my Shinohara/ Walthers curved TOS and checked the turnouts before buying, to avoid going below my minimum radius - they are notorious for overstating the radi....
In another instance, I had to scratchbuild a curved turnout for the top of my helix when none of the commercial products would fit - I discovered they wouldn't fit after purchasing several of them and trying them in the space. An expensive miss.....
short excerpt from long explaination...
SheldonBecause of the rail/wheel relationship theory that says under ideal conditions, the flange does not touch the rail.
Very good explaination.And I guess I was just looking at those Peco turnouts with a distorted eye. I was orinally understanding that those were curved diverging routes, but as I viewed them while mocking up my staging tracks I began to think that the very end of the diverging tracks were actually more straight than curved,....my error.
One advantage of these Peco turnouts is they occupy less linear length than many others (more compact).
Water Level Route railandsail What is a real quick and/or simple way to determine if they are Electrofrog, or Insulfrog? Look at the tip of the frog where the rails come together. If there is a small piece of black plastic, then they are insulfrogs. If metal, then electrofrog.
railandsail What is a real quick and/or simple way to determine if they are Electrofrog, or Insulfrog?
Look at the tip of the frog where the rails come together. If there is a small piece of black plastic, then they are insulfrogs. If metal, then electrofrog.
A few more thoughts:
Again agreed, I have no idea if rail/wheel theory really has any measureable effect on our model turnouts.
And, it depends on the application. Building a yard ladder, PECO curved frogs likely don't have any negetive effects.
But it really bugs me to use them to build a crossover - it's like the idea of putting two pieces of snap track back to back as an S curve, going right from one curve to the other direction curve with no striaght in the middle.
And then for me there is the PECO springs that have to be removed and the extra wiring to make them work the way I want.
Having build my own turnouts, I now much prefer the feed thru wiring and the seperate live frog. This type of wiring scheme works best with my Advanced Cab Control system. So Atlas is ready to use out of the box.
Is the Atlas code 100 a little "clunky"? Yes, agreed.
One thought on cost. As a construction professional I always look at time as well as materials when measuring cost. I know we are not paying anyone to build our layouts, but time is time, the faster, easier tasks go, the more we get done.
But more different materials, more detailed purchase lists, more steps in preping materials are all time factors which seem to eat up small savings very quickly - we see it all the time in our work. Not saying this is true about your choices, but there is that saying - penny wise and dollar (or pound) foolish.
ATLANTIC CENTRALI'm a little bit of a neurotic perfectionist, so I don't like the idea of randomly using different brands of track/turnouts without very specific reason. Next neurosis, I would not bother to change rail sizes just because track is hidden. BUT, Atlas code 100 turnouts work fine
Next neurosis, I would not bother to change rail sizes just because track is hidden. BUT, Atlas code 100 turnouts work fine
Neurotic is ok. I am somewhat of a perfectionsist with track laying myself. That said, I've mixed differing brands of track on my past two layouts for specific reasons, mainly that Atlas didn't offer #8 turnouts at the time, or large radius curved, or other specialty turnouts. I purchased mostly Walthers (made by Shinohara) code 83 turnouts to fill those needs. Since then Atlas has offered a #8, of which I bought one, but still have the Walthers for where they may be required.
As for hidden staging, I already have a good deal of code 100 track. In general code 100 is cheaper and more durable and if appearance is not important, then all the these combined reasons are for me compelling to continue to use code 100 in hidden staging on my next layout. Even if I didn't have a bunch of code 100 already, I'd probably go with it anyway because it would save on cost and being raised by depression era parents and not bleeding money, I like to keep costs down where ever possible.
I've used the Atlas code 100 turnouts for many years but really don't care for them and the large pothole at the frog; maybe thats just me but I'm ready to retire them on my next layout and substitute something else for the staging yard. You've made your point about Atlas turnouts well enough so no need to belabor it any longer on my behalf. You know what they say about repeating something over and over and expecting a different result - heading in to insanity territory. Maybe I'm getting there too on some topics.
As for curved frog, thanks for the theory discussion. I've tried to read up on turnouts over the past 10 years and so far there really doesn't seem to be a consensus that the curved frog is an issue in HO and that modelers have found no experiencial issues in that regard. I do like to consider all arguments as much as possible before making decisions on track to use.
Rio Grande. The Action Road - Focus 1977-1983
riogrande5761 ATLANTIC CENTRAL Brian, PECO code 100 turnouts are curved thru the frog. Look at the outer diverging route rail, it is a smooth curve all the way, no "straight" segment parallel to the frog or beyond. What is the equivelent you would use in code 100, and why is it you don't like the curved frog turnout? Is it just for looks? If so, for hidden staging, shouldn't be an issue?
ATLANTIC CENTRAL Brian, PECO code 100 turnouts are curved thru the frog. Look at the outer diverging route rail, it is a smooth curve all the way, no "straight" segment parallel to the frog or beyond.
Brian, PECO code 100 turnouts are curved thru the frog. Look at the outer diverging route rail, it is a smooth curve all the way, no "straight" segment parallel to the frog or beyond.
What is the equivelent you would use in code 100, and why is it you don't like the curved frog turnout? Is it just for looks? If so, for hidden staging, shouldn't be an issue?
OK, first, I'm a little bit of a neurotic perfectionist, so I don't like the idea of randomly using different brands of track/turnouts without very specific reason.
Next neurosis, I would not bother to change rail sizes just because track is hidden.
BUT, Atlas code 100 turnouts work fine.
Why no curved frogs? Why are they straight on the prototype?
Because of the rail/wheel relationship theory that says under ideal conditions, the flange does not touch the rail.
If a given wheelset is "in a curve", it is pushed toward the outside of the curve, even if the flange is not making contact. The wheel taper makes the outer wheel "larger" and the inner wheel "smaller", steering the wheel around the curve.
Which side is the frog gap on? The outside.
OK the guard rail will pull it over and prevent problems - BUT, it does that at greater friction in a curve than in a straight.
Turnout theory says the wheel is rolling the down the straight track, centered by gravity and the wheel taper. If the points are set to the diverging route, the "outside" wheel passes onto the closed point rail which is effectively a straight piece of rail that diverges at a very small angle.
As the wheel tries to continue straight the wheel tapper "climbs" the rail. Gravity and increasing wheel diameter steer the wheel into the new route, a very small change in direction.
The wheel continues straight again on the new path to the end of the moveable point rail, at which point it will enter the curve of the diverging closure rail, and turn for the known reasons, gravity and changing diameter as it tries to climb the rail.
NOW, at the end of the closure rail curve, right before the frog, the wheel now resumes straight track operation, gravity and the tapered wheel act once again to center the wheelset between the rails. This allows the wheelset to pass over the frog gap without the flange touching the side of the rail as it passes over the frog gap.
And, possibly allows the inner wheel flange to pass between the running rail and the guard rail without the added friction of the back of the wheel flange interacting with the guard rail.
All of this improves the chances that the outer wheel will pass over the frog gap smoothly and be well supported the whole time with no flange contact to risk interference.
So, how much does all this actually come into play with our models? I'm not really sure.
But there you have it, the engineering theory that allows a 70 ton freight car to change direction and move from one track to another.
Do the PECO code 100 turnouts work? Sure they do. Will I use them? No.
BUT, I never bought them in years past, I have no left over stock of them, I have no economic "dog" in this fight.
And Atlas code 83 turnouts are relatively in-expensive......