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Track Issue - Engines Derail

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  • Member since
    January 2018
  • 172 posts
Track Issue - Engines Derail
Posted by kenben on Tuesday, April 18, 2023 7:32 PM

I have several 6-axel engines that wil derail at the start of a curve at the end of an incline. Some have no problems. Others do. All are the same type 6-axel engines. Why do some stay on track and others come off? I've tried elevating the outside rail slightly to no avail.

Suggestons? Tips? 

Thank you.

  • Member since
    August 2022
  • 21 posts
Posted by Mike in NC on Tuesday, April 18, 2023 8:01 PM

I'd start by checking the wheel gauges on all the trucks along with verifing the track staying in gauge.    Next I'd check the coupler pin clearance and make a close examination of the engines undersides for anything that might catch.  

The scale or brand wasn't mentioned but if 3 rail then make sure the roller pickups are working correctly.

 

-Mike in NC,

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  • From: SE. WI.
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Posted by mbinsewi on Tuesday, April 18, 2023 8:07 PM

Run your locos in slow speed, and get your eyes right down there as close as possible, and watch what happens.  You'll see.  Use a small flash light if needed, but watch close.

It sounds like the trucks might be "lifting" a bit, causing the other axles to climb the rail.

Maybe you need more of an "easment" coming off that incline, and at the start of that curve.

Close inspection will tell you what's going on.

Mike.

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    March 2012
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Posted by PC101 on Tuesday, April 18, 2023 8:18 PM

mbinsewi

Run your locos in slow speed, and get your eyes right down there as close as possible, and watch what happens.  You'll see.  Use a small flash light if needed, but watch close.

It sounds like the trucks might be "lifting" a bit, causing the other axles to climb the rail.

Maybe you need more of an "easment" coming off that incline, and at the start of that curve.

Close inspection will tell you what's going on.

Mike.

 

Sounds like a start for the OP.

As I read the post, the train is going up the incline and derails going into the curve.

Maybe the train is going down the incline and derails going into the curve.

With the system shut down (dead track power), take a 12'' stainless steel ruler and slide it on it's long thin edge (the 12'' side) on one rail up the incline onto the curve and watch if you see any space appear between the ruler's ends and the rail, then do the same with the other rail. Space is not a good thing.

I agree with the first replyer. More infomation would be helpful like scale, brand of engines, engine going up the incline, engine going down the incline radius of the curve and where are the rail joiners located at? 

  • Member since
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  • From: Chi-Town
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Posted by zstripe on Tuesday, April 18, 2023 8:37 PM

mbinsewi

Run your locos in slow speed, and get your eyes right down there as close as possible, and watch what happens.  You'll see.  Use a small flash light if needed, but watch close.

It sounds like the trucks might be "lifting" a bit, causing the other axles to climb the rail.

Maybe you need more of an "easment" coming off that incline, and at the start of that curve.

Close inspection will tell you what's going on.

Mike.

 

Like Mike said........If You have any type of track problems at all....A six wheel truck will find it. For starters.......forget the track.... get a flat piece of glass, like you would find in a picture frame or flat mirror. Place engine with trucks on a sheet of loose-leaf paper, you should not be able to pull the paper from under the trucks if all wheels are sitting flat on it with the flanges. If You can pull the paper out that means when the engine is on the tracks the same thing happens on dips, kinks, tight out of gauge curves and so on. Kinks at rail joiners, number one problem with 3-axle engines.

Take Care! Smile, Wink & Grin

Frank

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    January 2018
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Posted by kenben on Tuesday, April 18, 2023 11:02 PM

Scale: HO

Track Peco 83

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Posted by kenben on Tuesday, April 18, 2023 11:10 PM

Happens as the front truck goes into the 22" curve at end of the up hill incline. The engines are ScaleTrains engines. Rail joiners are not in the area where the deailments are happening. 

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Posted by mvlandsw on Tuesday, April 18, 2023 11:55 PM

The transition from upgrade to flat may be too sudden. The lead axle may be held above the rail by the two following axles still on the upgrade. It then just goes straight instead of following the curve.

Mark

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    January 2010
  • From: Chi-Town
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Posted by zstripe on Wednesday, April 19, 2023 4:07 AM

mvlandsw

The transition from upgrade to flat may be too sudden. The lead axle may be held above the rail by the two following axles still on the upgrade. It then just goes straight instead of following the curve.

Mark

 

The above sounds like what is happening..............

Take Care! Smile, Wink & Grin

Frank

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    November 2013
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Posted by snjroy on Wednesday, April 19, 2023 5:49 AM

Hi there. 22" is tight for long 6 axle diesels. Make sure your track is level laterally in the curve/elevation. Make sure that your trucks sit flatly on the loco frames, as suggested by others.

Simon

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    July 2006
  • From: west coast
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Posted by rrebell on Wednesday, April 19, 2023 7:15 AM

Check your track if it is flex, had one spot where it was soposed to be one radius and it tightened ever so little and had an issue with some engines, luckly I was able to nudge it back to radius, guess it had moved before the caulk had compleatly set up.

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    January 2018
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Posted by kenben on Monday, May 1, 2023 1:58 PM

I've finally fixed the derailment problem i this curve. 6 of my engines now run perfectly through this curve. HOWEVER....

When it tested my ScaleTrains EMD SD40T-2 (SP), though it runs fine through this curve, it derails in several other places. Mostly when entering a turnout. The front wheels just come of the rails or the engine just stops and somehow causes a shortout. In checking the wheels and the under carrage of this engine, there is very little clearance between where the wheels sit on the track and the undercarrage clearing the turnout rails. STRANGE THING is I also have a very simular engine, a ScaleTrains SD40-2 (SF) that runs fine. Is there really a difference between a SD40T-2 and a SD40-2 that would cause one to derail all the time?

I'm so frustrated with this issue the fact my 2 BLI Paragon engines have major DCC issues where one doesn't eveb start up any more and the other seems to have issues getting power from rai to engine is it starts and stops all the time. Tracks and wheels all ave been cleaned. And I'm still a rookie at DCC.

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Posted by kasskaboose on Monday, May 1, 2023 4:49 PM

There's clearly a problem with the loco.  Have you tested it at a slower speed? 

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Posted by Doughless on Monday, May 1, 2023 4:59 PM

The track is likely twisted a bit to where the outer rail sits lower than the inner rail.  Six axle trucks are especially prone to finding these dips.  They are more rigid than 4 axle trucks, and when the inner wheels ride on the higher inner rail, the outer wheeles will ride over the lower outer rail and will derail.

Since you may not find the dip with your eye, watch carefully when the wheels come off the tracks.  Slip a piece of cardsock (cereal box) under the outer half of the ties at that spot to shim the outer rail higher.  You may want to shim several inches along the outer rail.  

- Douglas

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    May 2020
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Posted by wrench567 on Monday, May 1, 2023 7:37 PM

Either move the incline further from the curve or extend the easement right into the curve. Your asking a lot from the rigid frame six wheeled locomotive trucks. Just entering a 22 inch curve without easement is enough. But throwing in a vertical transition too may be too much.

       Pete.

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    December 2009
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Posted by 05c50 on Tuesday, May 2, 2023 6:24 PM

I had some six axle diesels that would derail in certain spots that I could not get a good view of what was happening. It was very frustrating trying to figure out the problem without getting a good view of it. Then it hit me, do what every 12 year old would do, use my cell phone to do a close up recording of the derailment. I was then able to play it back and stop it just as the wheel came off the rail.

 

.........Paul

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