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Thread: Flange-ways in our Turnouts

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    It seems obvious to me that if flangeways are deeper than flanges, there will never be a problem. Use bottomless chasms, if you want. The RP-25 standard is designed to give you smooth movement through turnouts, but every part has to match. Change the wheel width, and you'll get better-looking wheels, but the price is likely to be a "dip" as the wheel passes over a frog. I've done a lot of hand-laid turnout construction, and our club uses some "semi-scale" wheels with the narrower tread width. I test every turnout with a car that has the narrower wheels, and I can make it run almost flawlessly, but it requires a little cheating: keep the flangeway adjacent to the frog to the bare minimum, and make it up on the opposite (guardrail to stock rail) side. What that does is to keep the most sensitive area, at the tip of the crossing vee, to the minimum width. There's no way to prevent that gap from having the width of two flangeways side by side, so it's best to keep them as small as possible. And geometrically, that keeps the area as short as possible too.

    Of course, with a commercial turnout you'll have to live with the manufacturer's choice of dimensions. One thing you can do, if the flangeways are too wide, is to narrow them (not fill up the depth!) with a plastic shim. That should have the effect of keeping the passing wheels on the optimum path.
    "Against dirty track, the Gods themselves contend in vain."

  2. #42
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    Quote Originally Posted by John P View Post
    It seems obvious to me that if flangeways are deeper than flanges, there will never be a problem. Use bottomless chasms, if you want. The RP-25 standard is designed to give you smooth movement through turnouts, but every part has to match.
    I don't want bottomless Chasms! I'm unsure of what others might have problems with, as far as Flange-Ways are concerned. I'm saying that with ,025 deep flanges on our wheels, a .044 to .050 deep Flange-Way is too deep, when you consider that the wheels will not cross the frog without falling into the deep Flange-Ways of my turnouts.

    In fact, using my NMRA Mark IV Standards Gauge, the only dimension I find lacking on on my Atlas Custom Line Turnouts, are the Flange-Way Depths. I should think being .020 to ,025 deeper than the Flange-Way gauge on the NMRA Standards Gauge would be an out-of-tolerance situation. However, with the deeper Flange-Ways, do my turnouts work? Yes!

    This has been an interesting thread, I have been splitting hairs over the depth of the Flange-Way as I think the manufacturers could do a better job. Possibly the fix is to narrow-up the Flange-Ways to a more prototypical width. It's all the manufacturer's call.
    Last edited by NP2626; 02-14-2018 at 04:58 AM.
    Mark D.

    Opinions given are my own and not meant to ruffle any feathers.
    Northern Pacific, really terrific!

  3. #43
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    Quote Originally Posted by John P View Post
    .....
    I test every turnout with a car that has the narrower wheels, and I can make it run almost flawlessly, but it requires a little cheating: keep the flangeway adjacent to the frog to the bare minimum, and make it up on the opposite (guardrail to stock rail) side. What that does is to keep the most sensitive area, at the tip of the crossing vee, to the minimum width. There's no way to prevent that gap from having the width of two flangeways side by side, so it's best to keep them as small as possible. And geometrically, that keeps the area as short as possible too.
    I have a couple of questions here. Those flangeways next to the frog are often termed the wing rails?

    if you make them a snug fit while keeping the outer guard rails 'loose', don't you run the risk that the wheel will 'pick the frog' in the wrong direction?

    I had been thinking that I needed a closer fitting of the outer guard rail,...combined with a somewhat rigid truck frame, to keep things running smoothly??

  4. #44

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    Quote Originally Posted by beiland View Post
    I have a couple of questions here. Those flangeways next to the frog are often termed the wing rails?

    if you make them a snug fit while keeping the outer guard rails 'loose', don't you run the risk that the wheel will 'pick the frog' in the wrong direction?

    I had been thinking that I needed a closer fitting of the outer guard rail,...combined with a somewhat rigid truck frame, to keep things running smoothly??
    You want the flangeway on the outer rails to be a good fit so as to pull the other wheel away from the frog.

    Ideally you want the depth of the flange way in the frog area such that the wheel there rides on the flange and doesn't drop down into the gaps. But if you have some wheels with deep flanges those wheels won't roll smoothly through the frog.

    My Peco Code 83 Streamline turnouts have shallow flangeways in the frog area and a few older locos with deep flanges bump a bit as they go through.

    Frederick

  5. #45
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    Quote Originally Posted by fcwilt View Post
    You want the flangeway on the outer rails to be a good fit so as to pull the other wheel away from the frog.
    That's what I thought originally as well, but now we are hearing a different story.

    Ideally you want the depth of the flange way in the frog area such that the wheel there rides on the flange and doesn't drop down into the gaps. But if you have some wheels with deep flanges those wheels won't roll smoothly through the frog.
    That is not always true,.... needing those flanges on the wheels to be supported from the depths. If we tried to make those depths all exactly the same we might not be able to run a wide variety of trains. And since depth does not seem to be that great of a problem with derailments, I opt to have to have some tolerance to the depth of my flangeways.

  6. #46

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    Quote Originally Posted by beiland View Post
    That's what I thought originally as well, but now we are hearing a different story.


    That is not always true,.... needing those flanges on the wheels to be supported from the depths. If we tried to make those depths all exactly the same we might not be able to run a wide variety of trains. And since depth does not seem to be that great of a problem with derailments, I opt to have to have some tolerance to the depth of my flangeways.
    Which is why I said "ideally" and mentioned the problem with wheels having flanges that were deeper.

    I have not had a problem with derailments because of the shallow Peco flangeways in the frog area, just the "bumping" of those cars and engines that have the deeper flanges.

    Frederick

  7. #47
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    I would challenge all of us to find wheel flanges deeper than .025. If it is on a locomotive, that's one thing, if on rolling stock, why wouldn't you change the wheels out for wheels with .025 flanges.
    Mark D.

    Opinions given are my own and not meant to ruffle any feathers.
    Northern Pacific, really terrific!

  8. #48
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    I think we're getting close to the heart of what is my "Bone to Pick". That is "Tolerances". NMRA Standard S-3.2 describes the following measurements: Gauge at Frog, Check Gauge, Span, Flange-Way, Points and gives Tolerances for all five of those dimensions. However, when it describes the H dimension (The depth of the Flange-Way), it only gives .025 as a minimum for both HO and OO scale! Had I been working with whatever committee came up with S-3.2, I would have felt that there should be a maximum depth, .025 +.005.

    NMRA S-3.3 (Deep Flanges) describes dimension H as .047 deep (this would seem to describe Atlas Custom Line Turnouts).

    Certainly manufacturers can keep tighter tolerances than what HO standards currently use. For instance: I don't understand why the space between the point rail and stock rail are so wide; or, why the Flange-Ways are so big. However, these dimensions do work; so, other than the comment just made, I am good with how things are.

    Again, I want a Code 110 wheel width, because of the slop built into track dimensions; but, like everyone else. I want my layout to look as real as I can get it. In the end, how important is any of this, anyway? It's in the "Eye of the beholder" Possibly, where I to start over in Sn3, I would hand lay and correct some of these things on my own, simply because I've "Thrown the gauntlet down" for myself!
    Last edited by NP2626; 02-15-2018 at 05:55 AM.
    Mark D.

    Opinions given are my own and not meant to ruffle any feathers.
    Northern Pacific, really terrific!

  9. #49
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    I also believe that if we were to completely go "proto scale", we would introduce problems simply due to the fact that the size and weight of our models don't "Scale Out" to things which work in full scale.
    Mark D.

    Opinions given are my own and not meant to ruffle any feathers.
    Northern Pacific, really terrific!

  10. Default

    There's no spec for the flangeway max depth because the flanges should never reach that far! Hence "bottomless chasms"--make it as deep as you want, as long as it's deep enough. Should I not make cracks like that? (Ha ha)

    Wheels shouldn't take the wrong route through a frog, regardless of whether the guard rail keeps the flanges away from the frog, even if they're set for minimum width adjacent to the frog. Set things up so the tolerances match RP-25, and it will work. The reason to keep the flangeway adjacent to the frog to minimum size is to make the gap between the two running rails in the "throat" region as small as possible, which also makes that area as short as possible along the length of the turnout. This has the effect of reducing that "dip" effect as wheels roll by. If you use narrow wheels which don't meet RP-25, it's the best result you can get. It can certainly be good enough to avoid derailments.

    If anyone's interested, there's a Handlaid Track group on Yahoo Groups. It's hasn't been very active lately, but a discussion about basic track geometry should get some responses!
    "Against dirty track, the Gods themselves contend in vain."

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