# locomotive derailing



## danpuckett (Dec 31, 2014)

I have a Kato locomotive DCC with 6 wheel trucks. This is a great unit but derails at almost every turnout. The turnouts are Atlas HO scale. I would not be quite as perturbed if I did not watch my Atlas DCC locomotive with 4 wheel trucks run the entire course with no issues. All help and insight will be appreciated. The layout has 22" radius.


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## Chet (Aug 15, 2014)

Check and make sure that all the wheel s are in gauge for a starter.


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## wvgca (Jan 21, 2013)

a check with an NMRA standards gauge should give you some insight to the derailing problem ... if you don't have one, a micrometer can be used ... track inside spacing is 0.0603 +.002 -.007, and wheel width [flange to flange outside] should be 0.0051 +.010 -.002 .. specs available on the NMRA standards pages ...


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## CTValleyRR (Jul 26, 2014)

Great loco but derails all the time.... OK, whatever you say. 

What specific model is it? I've had trouble with models that have very long trucks binding on turnouts. Also, what kind of turnouts are they? Code 100 or 83? And are they snap switches, and if so, are you sure they're the 22" radius models?


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## MtRR75 (Nov 27, 2013)

Since the loco derails at almost every turnout, I would start with engine issues. If the wheels turn out to be in gauge, next run the loco very slowly over a turnout. Put a flashlight behind it and bend down and look under the loco to make sure that no part of the loco is hanging too low and catching on the turnout. I had this happen once, when a screw had worked its way loose. Also couplers that are hanging too low can catch on turnouts.

If nothing is catching on the bottom, watch the slow movement to see where the first wheel jumps over the rail. Check the width of the track at that point, with an NMRA guage.

Also, play with the trucks and make sure that they rotate freely and do not bind up or catch on parts of the loco. (I've had this happen a couple of times on freight cars.)


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## DonR (Oct 18, 2012)

Assuming you have carefully checked the trucks
as suggested the next step is to look at the turnouts.
Some locos just do not like Atlas turnouts.

MTrr has the right idea.

Get a bright flashlight then get down very close to a turnout where
the loco derails, then run the loco at the slowest possible speed and
watch where the first wheel starts to lift. STOP. Repeat. If the same thing
happens that's where the fault is. Look closely and see what is pushing
the wheel up.

And one other thought. Are the trucks solidly mounted to the frame
or do they excessively rock back and forth, or laterally.

Don


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## MtRR75 (Nov 27, 2013)

DonR said:


> Look closely and see what is pushing
> the wheel up.


I find that if it looks like nothing is pushing the wheel up, check the wheel on the opposite side. Sometimes the track is a little to wide in places (especially in short-radius Atlas turnouts) and the wheel on opposite side drops down onto the ties, first. When the track tightens back up, the wheel on your side gets pushed up and over the rail.


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## D&J Railroad (Oct 4, 2013)

Check the swing of the trucks to be sure they aren't hanging up on the coupler pocket or step ladders of the loco.


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## Cycleops (Dec 6, 2014)

Unlikely the wheels are out of gauge. If it's an older model it may have deeper flanges which are incoompatitable with your Atlas turnouts, causing derailing, I'm guessing over the frogs. Try it with another turnout brand which uses code 100 rail.


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## danpuckett (Dec 31, 2014)

The locomotive I am having the most problems with is a brand new Kato. It does have 6 wheel trucks.


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## danpuckett (Dec 31, 2014)

what turnouts do you suggest? I am using code 100 Atlas Flex track.


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## danpuckett (Dec 31, 2014)

I am not sure what you mean, "the wheels might be out of gauge". I am new at this. I run some O gauge stuff also that runs flawlessly. The HO is a learning curve for me.


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## Cycleops (Dec 6, 2014)

Try some Peco, they can handle most anything, I can't give you any guarantees but if it then woks at least you will know the problem.


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## Cycleops (Dec 6, 2014)

danpuckett said:


> I am not sure what you mean, "the wheels might be out of gauge". I am new at this. I run some O gauge stuff also that runs flawlessly.


The back to back measurement might be at variance with the standard. I believe O gauge can be rather less exacting and still perform.


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## CTValleyRR (Jul 26, 2014)

danpuckett said:


> I am not sure what you mean, "the wheels might be out of gauge". I am new at this. I run some O gauge stuff also that runs flawlessly. The HO is a learning curve for me.


So before you go running out and changing turnouts, if it's only this one loco that misbehaves, it is almost certainly a problem with this loco, not the turnouts.

Gauge, no matter what scale (even prototype) is the distance between the inside edges of the rails. Rail is said to be correctly gauged when the rails are the proper distance apart, plus or minus a very small variance (thousandths of an inch in HO scale). Rolling stock wheels also have to be properly gauged to operate well on the track. That is, the distance between the outer edges of the flanges has to be slightly less than the track gauge. Wheels that are not far enough apart will allow one wheel to drop off the inside edge of the rail; too far apart and they bind against the rails, particularly in curves and turnouts.

The NMRA sells standards gauges to quickly check the most common measurements in the various scales. On one edge is a pair of notches, correctly spaced for the flanges on your rolling stock. If your wheels fit in these notches, your wheels are correctly gauged and you need to look elsewhere for your solution. If not, you've found the problem.

NMRA standards gauges are available at most hobby shops that sell train supplies, or on the internet.


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## danpuckett (Dec 31, 2014)

wvgca said:


> a check with an NMRA standards gauge should give you some insight to the derailing problem ... if you don't have one, a micrometer can be used ... track inside spacing is 0.0603 +.002 -.007, and wheel width [flange to flange outside] should be 0.0051 +.010 -.002 .. specs available on the NMRA standards pages ...


Inside track spacing...is the dimension .0603 inches, meters, feet or what? I do not have a NMRA gauge.


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## CTValleyRR (Jul 26, 2014)

danpuckett said:


> The locomotive I am having the most problems with is a brand new Kato. It does have 6 wheel trucks.


6 wheel trucks have more trouble handling tight curves. This could be part of your problem iff it is your longest piece of equipment.

The brand newness of the loco doesn't matter. Even the best manufacturers have the occasional problem.


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## CTValleyRR (Jul 26, 2014)

danpuckett said:


> Inside track spacing...is the dimension .0603 inches, meters, feet or what? I do not have a NMRA gauge.


Go back and read my post with the definitions. His measurements are in inches. But a standards guage is far easier. And really, while I understand your frustration and the lack of clarity, with a little logic, you could have figured out the units on your own.

You may have gotten a sense of the gauge's utility from previous posts. If you are that amazingly lucky person who never has an issue (and this thread proves that you're not), you don't need one. If you intend to stick with this hobby, it is probably the single most important tool you can have for troubleshooting and repair. I strongly recommend that you get one. They are neither expensive nor hard to find.


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## Cycleops (Dec 6, 2014)

Where is it derailing, when the turnout is set straight or off to the right or left? Could be the radius on the Atlas is too sharp for the six wheel trucks.


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## Old_Hobo (Feb 20, 2014)

By "inside track spacing", is he referring to the space between the tracks?

So in H.O., inside track spacing is 0.0603 inches????? That's not right.....that's less than 1/10 of an inch, and just by looking, I can tell that the spacing is over half an inch....

I do believe it should be 0.603 inches.....he had a zero after the decimal, before the six, that should not be there.......but I could be wrong.....it's happened before.....


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## wvgca (Jan 21, 2013)

old_hobo .. good catch . i had too many zeros .. oops..
should be 0.603 wheels, / 0.651 track, both in inches ..
also another thought .. track radius mentioned was 22 inch i think, but no mention of turnout models??.. if they are snap track rather than custom line, the snap track if i remember correctly is pretty tight, but if there are other six axles locos that go through okay the problem one might have trucks that could be not swiveling enough??


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## traction fan (Oct 5, 2014)

*Track guage*

Danpucket;

I strongly agree with the prior recommendation to get an NMRA (National Model Railroad Association) standards gauge. 
It will pay for itself many times over in reduced frustration!
After all we're in this hobby to relax, not get driven up the wall, trying to figure out why things happen! 
The gauge comes with easy to understand, illustrated, instructions. The most likely problem is that one or more of that one loco's axles has the two wheels mounted on it either too close to each other, or too far apart from one another. That's what "out of gauge" means. Likewise the rails of any track can be too close or too far apart. That is also called "out of gauge".
When both, ALL the wheels on the loco, AND ALL the rails of that turnout are correctly spaced; ("in gauge") then the wheels will fit the track properly and the derailments will stop.
Conversely if even one pair of wheels, or one short piece of track within the turnout,
are NOT properly spaced, (A.K.A. "out of gauge"), the derailments will continue indefinitely.
The NMRA standards gauge can also check many other things that can be wacko in a turnout Like flangeways. I won't get into that now, the directions with the NMRA gauge will explain it better than I can here.
Start using this truly "must have" tool with the simple adjustments like wheel spacing. I suspect that's where the problem lies.


Hope this helps you
Traction fan


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## MtRR75 (Nov 27, 2013)

traction fan said:


> When both, ALL the wheels on the loco, AND ALL the rails of that turnout are correctly spaced; ("in gauge") then the wheels will fit the track properly and the derailments will stop.


Well, maybe derailments will stop and maybe they won't. There are other possible causes of derailments besides wheels and track being out of gauge. Some of the other reasons have already been mentioned in this thread. But wheel and track gauge is the first place to look when derailments occur repeatedly.


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## CTValleyRR (Jul 26, 2014)

wvgca said:


> old_hobo .. good catch . i had too many zeros .. oops..
> should be 0.603 wheels, / 0.651 track, both in inches ..
> also another thought .. track radius mentioned was 22 inch i think, but no mention of turnout models??.. if they are snap track rather than custom line, the snap track if i remember correctly is pretty tight, but if there are other six axles locos that go through okay the problem one might have trucks that could be not swiveling enough??


Yeah, sorry about that. I read it fast and didn't notice the extra zero either.


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## CTValleyRR (Jul 26, 2014)

MtRR75 said:


> Well, maybe derailments will stop and maybe they won't. There are other possible causes of derailments besides wheels and track being out of gauge. Some of the other reasons have already been mentioned in this thread. But wheel and track gauge is the first place to look when derailments occur repeatedly.


Right, but this is one of the most obvious sources. The OP seems to be fighting the suggestion that there could be anything wrong with his loco, though. It will be intersting to see what he discovers.


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## Cycleops (Dec 6, 2014)

Anyone taking bets on the track or the loco?


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## DonR (Oct 18, 2012)

I have eight DCC diesel locomotives, 2 of which are
identical FAs. The newest of that pair must be consisted
as the lead loco else one truck will derail, anywhere, and no
other loco or car does. However, as it breaks in it seems
to be less liable to derail. Running as the lead, no
problem, as the following, derails.

Strange animals these beasts be.

Don


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## CTValleyRR (Jul 26, 2014)

I'll put money on LOCO.


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