# Kato SD45 Derailing



## xrunner (Jul 29, 2011)

It happens coming out of a turn to straight track. I have 6 other engines and none of them derail at that spot. In fact I have a Kato SD40 that really appears identical underneath and it doesn't derail there. I spent 2 hours experimenting and couldn't find a problem with the track or engine. It looks perfect.

Does it possibly need more weight? It weighs the same as the SD40 though. What are the weight ranges for N scale locos?

Is it another issue? I'm confused.


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## JohnAP (May 4, 2011)

Did you check the gauge of the wheels?


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## xrunner (Jul 29, 2011)

JohnAP said:


> Did you check the gauge of the wheels?


Yep, perfect. I can't see a thing wrong with the track or the engine/wheels.

How about the weight? I weighed the SD45 and an SD40 and they both weighed about 3.45 oz. I weighed my Sd70 ace and it weighs 3.9 oz. So, the weight of an N scale engine can at least go up to 3.9 oz. I don't kow what else to possibly look at.


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## waltr (Aug 15, 2011)

What about how much the trucks pivot?
Is there any thing keeping the trucks from pivoting? like a wire connection.

Does the curve to straight have an easement or just x radius to straight?

Does it derail at very slow speeds?


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## xrunner (Jul 29, 2011)

waltr said:


> What about how much the trucks pivot?
> Is there any thing keeping the trucks from pivoting? like a wire connection.


No.



> Does the curve to straight have an easement or just x radius to straight?


No easement, but all my other engines do not derail there.



> Does it derail at very slow speeds?


No.


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## JohnAP (May 4, 2011)

Maybe a slight lateral misalignment of the rail joints, causing the wheels to "pick" the point?


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## xrunner (Jul 29, 2011)

JohnAP said:


> Maybe a slight lateral misalignment of the rail joints, causing the wheels to "pick" the point?


Probably that was it.

It's running OK now. I added some weight and it didn't help. I then took apart the track, removing 2 curved pieces of track. If you feel the ends of the track where it was cut at the factory, you could feel tiny nicks - and I do mean _tiny_. These nicks weren't making my other engines derail either. Why? They all are Kato and basically have the same wheels.

So I filed the tiny nicks away, and now it doesn't derail. Go figure. hwell:


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## powersteamguy1790 (Mar 26, 2012)

xrunner said:


> Probably that was it.
> 
> It's running OK now. I added some weight and it didn't help. I then took apart the track, removing 2 curved pieces of track. If you feel the ends of the track where it was cut at the factory, you could feel tiny nicks - and I do mean _tiny_. These nicks weren't making my other engines derail either. Why? They all are Kato and basically have the same wheels.
> 
> So I filed the tiny nicks away, and now it doesn't derail. Go figure. hwell:


 At least you were able to find the problem. :thumbsup: It doesn't take much too cause derailments of any locomotive.


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