# Loco derails on frog



## Rondar (11 mo ago)

My Intermountain EMD SD40-2 front left wheel when traveling westbound derails when it gets to the frog (Atlas code 86 manual switch). This only happens when pulling stock and with loco facing forward. I've filed the frog down some and that didn't help. I've watched at track level and the seems to move up just enough to derail or lose connection for a milli-second. This is a brand new out of the box loco. Is there something I didn't know to take off the trucks so they move more freely? I'm totally new to the hobby so any helpful info would be appreciated


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## J.Albert1949 (Feb 3, 2018)

You could check the wheelsets on the problem truck for the correct gauge.
(Although my guess is that they're all ok)

Do you have another switch you could substitute for the one that's giving you problems? Sometimes "that's all that it takes"...


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## MichaelE (Mar 7, 2018)

Check the depth of the flangeways on the frog and the wing rails.


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## Severn (May 13, 2016)

i've had some clunky transitioning at frogs and i think micheal might have a great point. i can't say i've done this myself but i saw a vid of a guy doing such for this reason. maybe it's related. ive been considering doing it myself in fact. i want smooth operation.


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## OilValleyRy (Oct 3, 2021)

MichaelE said:


> Check the depth of the flangeways on the frog and the wing rails.


Yup. 
Especially as you stated you watched closely and saw the wheel rise as it passed through. Odd that it doesn’t happen in reverse, but could be some flash or deformation on the plastic part at one end. 
Start by filing down the end of the frog only, rounding out that flange way edge for a better transition. If the wheel still rises, file the full length of the flange way. 
One would need a set of needle files (sometimes called jeweler files) for this.

And J.Albert is right. A track/wheel gauge will be very helpful. A good investment, not costly.


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## CTValleyRR (Jul 26, 2014)

Definitely second the recommendation for getting a Standards Gauge in the correct scale. That's the best way to solve a lot of these issues.


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## Rondar (11 mo ago)

J.Albert1949 said:


> You could check the wheelsets on the problem truck for the correct gauge.
> (Although my guess is that they're all ok)
> 
> Do you have another switch you could substitute for the one that's giving you problems? Sometimes "that's all that it takes"...


I don't have another switch. The switch on opposite side has issues too lol.


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## CTValleyRR (Jul 26, 2014)

Rondar said:


> I don't have another switch. The switch on opposite side has issues too lol.


We have an old saying in troubleshooting: if it happens to multiple pieces of rolling stock at one spot, suspect the track. If it happens to the same piece at multiple spots, suspect the track.


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## Rondar (11 mo ago)

OilValleyRy said:


> Yup.
> Especially as you stated you watched closely and saw the wheel rise as it passed through. Odd that it doesn’t happen in reverse, but could be some flash or deformation on the plastic part at one end.
> Start by filing down the end of the frog only, rounding out that flange way edge for a better transition. If the wheel still rises, file the full length of the flange way.
> One would need a set of needle files (sometimes called jeweler files) for this.
> ...


The picture shows where it rises. Is that normal for the plastic to be above the rail and can I file that down? I'm going to a show Saturday I'll get a gauge there.


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## JeffHurl (Apr 22, 2021)

If it's having the same trouble on more than one switch, then it is could be the wheel flanges being too large rather then the depth of the flangeways being too shallow.


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## kilowatt62 (Aug 18, 2019)

Atlas turnouts. Sorry to say but, that is More than likely the source of the problem at hand. 
I’m sure the member here by the name of Traction Fan will be along soon enough to comment. He has a few files on how to deal with These turnouts. Especially the “Snap Switch” version. Not that what has already been mentioned is null, its just that Traction’s files go into great detail to help you.


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## Rondar (11 mo ago)

JeffHurl said:


> If it's having the same trouble on more than one switch, then it is could be the wheel flanges being too large rather then the depth of the flangeways being too shallow.
> [/QUOTE
> Filing it down will help?


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## JeffHurl (Apr 22, 2021)

I really don't know... I would get the standards gauge and test the flangeways. I didn't remember that you were using Atlas turnouts. They don't have the best reputation for being great. But as KW62 said, @traction fan has a lot of good info and advice about how to make them better.


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## Rondar (11 mo ago)

kilowatt62 said:


> Atlas turnouts. Sorry to say but, that is More than likely the source of the problem at hand.
> I’m sure the member here by the name of Traction Fan will be along soon enough to comment. He has a few files on how to deal with These turnouts. Especially the “Snap Switch” version. Not that what has already been mentioned is null, its just that Traction’s files go into great detail to help you.


Cool I hope he replies lol. I'm waiting for the build your own comments lol. My skills aren't there yet.


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## mesenteria (Oct 29, 2015)

Large wheel flanges should still run through a frog, although not at normal 'track speed', say 30 mph and above...which would be a pain. The lifting tells me that the gauge is wrong, either the guards need shimming or the wheel spacing is wrong. I don't see that the flanges are especially out-sized, but I don't have the best eyesight.
The appropriate scale NMRA gauge has flange-path check gauge (for RP-25 flanges), and of course flange gauge as well.


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## Rondar (11 mo ago)

mesenteria said:


> Large wheel flanges should still run through a frog, although not at normal 'track speed', say 30 mph and above...which would be a pain. The lifting tells me that the gauge is wrong, either the guards need shimming or the wheel spacing is wrong. I don't see that the flanges are especially out-sized, but I don't have the best eyesight.
> The appropriate scale NMRA gauge has flange-path check gauge (for RP-25 flanges), and of course flange gauge as well.


It goes over the switch one time just fine any speed. Second time is when issue happens.


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## OilValleyRy (Oct 3, 2021)

Well wheels rising like that is not normal.
While the wheels could be out of gauge, I don’t think that’s the case. It’d be derailing on curves too, or not sitting properly anywhere. But mainly, wheels are machined metal. Frogs are injection molded plastic. 9 out of 9.1 times, the plastic will be the problem over machined metal.

It is really hard to see the flange on that wheel. Do a thorough inspection of the frog endsand adjacent guard rail. I _think_ the flange way is shallower than it should be; but I wouldn’t be surprised if some defect in the guard rail is forcing the wheel to the outside, and then leading it to rise up.

You said it’s code 83 but those ties sure look black to me. 
You didn’t mention what size turnout that is. #6? #4?


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## rrman987 (Aug 29, 2021)

On my layout I have two consecutive Ross tinplate left hand switches leading into sidings and two consecutive Ross tinplate right switches leading out of same siding. Going into switch (either left or right hand traveling) curve, my MTH N&W Y6b front engine would derail on the second following switch's curve. After alot of observing, my solution was to glue a small piece of plastic just before the curve point met the stock rail. Its height filled the area between the rail ball bottom and rail mounting flange. (All clear as mud right) What this did was keep the front engine's flange moving ahead until it intersected the curved point rail and flange remained on curved rail.

I kind of copied this from how Lionel did this for their O22 switches. If you looked closely, their stock rail was formed such that there was a "pocket" the curved rail moved into so the flange rolled ahead until it caught the curved rail. The pocket had no effect on flanges for straight ahead movements.


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## CTValleyRR (Jul 26, 2014)

Rondar said:


> It goes over the switch one time just fine any speed. Second time is when issue happens.


So I'm going to restate this a little bit. You NOTICE this issue on the second run, because whatever happened actually started on the first pass, throwing things just enough out of alignment that the wheels come off on the second one.

You need to upgrade or replace your turnouts in the ways discussed above. At least start testing and ruling out some of the issues that have been suggested. That's the only way to troubleshoot these problems (and you MUST actually test them, not assume it's not a problem).


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## traction fan (Oct 5, 2014)

Rondar said:


> My Intermountain EMD SD40-2 front left wheel when traveling westbound derails when it gets to the frog (Atlas code 86 manual switch). This only happens when pulling stock and with loco facing forward. I've filed the frog down some and that didn't help. I've watched at track level and the seems to move up just enough to derail or lose connection for a milli-second. This is a brand new out of the box loco. Is there something I didn't know to take off the trucks so they move more freely? I'm totally new to the hobby so any helpful info would be appreciated


Rondar;

Lets try to isolate the problem.
Is it the locomotive, or the turnout, or possibly the combination of the two? Do other locomotives, or cars, derail on this same turnout? Does that particular SD40-2 derail on other turnouts? If other equipment derails on that turnout, then the turnout may be the culprit. Particularly if the same rolling stock does not derail on other turnouts.
If the problem SD40-2 can travel through other turnouts without derailing, that's more evidence against the turnout.

Please! Never file a frog point.
First off, It won't really fix any known problem, and worse, it can actually create a problem, a short circuit between the rails just below the plastic of that frog.

You should check all the wheels of the SD40-2, and several critical points on the turnout, with an NMRA standards gauge made for your scale. (N-scale, HO-scale etc.) If you don't have a gauge, get one. It is an essential tool for any model railroad. The gauge costs only about $12 and is an excellent investment. You can order an NMRA gauge from www.modeltrainstuff.com or www.trainworld.com If you are lucky enough to have a local train store, they may have the gauge in stock, or could order it for you.

The flangeways of nearly all* brands of commercial turnouts are too wide, to meet the specs. incorporated into the NMRA gauge. This fact often causes "picking the points" & other derailments. Those flangeways are also too deep, (which causes "frog bounce" where wheels first drop down into the frog, and then get dragged back up when they hit the point of the frog. This causes the cars to sway side-to-side and bounce a bit up-&-down.
"Frog bounce" is what has caused many a newbie, (including me when I started out about half a century ago.) to file down the point of the frog. While this might seem logical, it doesn't work, because the frog point isn't the problem. As mentioned, it can, and often has, caused a short circuit.

The real fixes for most turnout problems are shown in the files "Improving Atlas Turnouts 1 & 2 attached below. The first deals with the HO-scale, Atlas, "Snap Switch" turnout.
Starting on page eight, it shows an NMRA gauge being used to fix some of the design problems in Atlas, (& other brands of) commercial turnouts. The second file concerns the N-scale Atlas, "Snap Switch" turnout. Much of the info in both files applies to other brands of turnouts too.
If you follow the direction sheet that comes with the NMRA gauge, and reference the files, you should be able to correct the derailment problem you have.

Good Luck; & let me know what happens;

Traction Fan 🙂

* The exception is Micro Engineering turnouts. Their flangeways are actually a bit too narrow, unlike the too wide flangeways on other brands. The slightly too narrow flangeways on M-E turnouts can easily be fixed. One pass with a Dremel tool, or a little filing does the trick. Micro Engineering turnouts are otherwise very reliable.


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## traction fan (Oct 5, 2014)

Severn said:


> i've had some clunky transitioning at frogs and i think micheal might have a great point. i can't say i've done this myself but i saw a vid of a guy doing such for this reason. maybe it's related. ive been considering doing it myself in fact. i want smooth operation.


 Severn;

MichaelE is correct. The flangeways of nearly all commercial turnouts, (except Micro Engineering) are indeed too deep. They are also too wide. Some thin styrene shims, and a little glue, will fix both problems.
The "flangeways" tabs on an NMRA gauge should slide through the flangeways of a turnout smoothly, but without side-to side play. The bottom of a flangeway should just touch the bottom of the tab. If shims are added to prevent horizontal play, the likelihood of derailments drops off a lot. If the points are sharpened, and a slot in the stock rail lets each point "hide" in the recess, "picking the points" becomes all but impossible, assuming all wheels have been set to proper gauge.

The shims that bring the bottom of the frog flangeways up to just touch the gauge's "flangeways" tab, prevent "frog bounce" where the wheel first drops down into the frog, and then gets dragged back up when it hits the frog point. This causes cars to bounce vertically, and sway side-to-side. This is likely the "clunky transitioning" you have seen. The file "Improving Atlas turnouts" shows the shim process beginning with the photos on page 8. 

Traction Fan 🙂


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## Rondar (11 mo ago)

traction fan said:


> Rondar;
> 
> Lets try to isolate the problem.
> Is it the locomotive, or the turnout, or possibly the combination of the two? Do other locomotives, or cars, derail on this same turnout? Does that particular SD40-2 derail on other turnouts? If other equipment derails on that turnout, then the turnout may be the culprit. Particularly if the same rolling stock does not derail on other turnouts.
> ...


Thank you for sharing some wisdom. I only have one loco so can't compare anything. And it is the dreaded Atlas snap track I have a lefthand and righthand manual switches. I'll be looking for a gauge tomorrow. I'll follow your file instructions. I was investigating today and not derailing after filing some parts of the frog....oops lol. Only problem now is loco loses power for a milli-second when it goes over both frogs. And said wheel gets lifted a tiny bit but not enough to derail.


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## traction fan (Oct 5, 2014)

Rondar said:


> Thank you for sharing some wisdom. I only have one loco so can't compare anything. And it is the dreaded Atlas snap track I have a lefthand and righthand manual switches. I'll be looking for a gauge tomorrow. I'll follow your file instructions. I was investigating today and not derailing after filing some parts of the frog....oops lol. Only problem now is loco loses power for a milli-second when it goes over both frogs. And said wheel gets lifted a tiny bit but not enough to derail.


Rondar;

You're welcome!

Hmmm? I wonder if the reason for your loco "loosing power for a millisecond" could be due to a short created when you filed the frog point? If you want to check my theory, try running the loco over the frog with the room light out. If you see a momentary spark, I'm right. If not, I'm wrong. It wouldn't be the first time I was wrong. Just ask my wife! 

By the way, your photo shows the wheel riding high on what appears to be the plastic "rail" of the frog, which is higher than the metal rail feeding into it. I'm not sure what that's about, since I gave up using Atlas turnouts many years ago. While I don't advocate filing the plastic down on frogs in general, the spot I was cautioning you never to file is the point, which is in the center of the frog, where two short metal rails (almost) meet. Those rails continue on under the black plastic frog point. The two rails are of opposite electrical polarities, and if the very thin layer of black plastic over them is removed, a metal wheel will short them to each other.

Atlas "Snap Switch" turnouts are not the best. In fact, they're the second-worst on the market. (Deposed by the truly awful Bachmann EZ-Track turnouts.) That said, most of their problems are fixable, and if you install some, or all, of the fixes in the file, they should, semi-magically, turn into pretty reliable turnouts. Since you only have two of the Atlas turnouts, I recommend you seriously consider Peco, or Micro Engineering, or Walthers, high quality turnouts for any further turnout purchases, and perhaps as eventual replacements for the low quality Atlas Snap Switch ones.

NOTE: Atlas snap switches have a unique geometry, with one curved route, and one straight route. This makes them easy to fit into Atlas track plans by inserting a snap switch in place of a piece of curved, or straight, snap track.
This substitution will not be as easy with any of the better brands of turnout, which have two straight routes, or in some cases, two curved routes, but not one of each in the same turnout. Some flex track can overcome this "fitting-in" problem. Take up a section or two of each track that connects to the spot where a decent turnout is replacing an Atlas turnout, and cut the track to fit.

Below is another file on turnouts in general. If you ever get to the point of "train insanity" where you find yourself desperately wanting to read more of my files,* (Say before building a new layout) they are all in the "Beginner's Q &A " section of this forum, inside a thread called "Help a new modeler to get started."

* That would require being pretty darn desperate! 

Good Luck & Have Fun;

Traction Fan 🙂


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