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6 axle diesels and tight curves

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  • Member since
    March 2008
  • From: O'Fallon, MO
  • 96 posts
Posted by kbaker329 on Thursday, October 2, 2008 2:28 PM

I usually run 2 engines at a time, 1 4 axle and 1 6 axles.  I have never had an derailment where both trucks were off of the track.  The majority of the derails are the lead axle on the front truck.  Occasionally it is the the lead axle of the rear truck.

Thanks for the input on removing an axle, has anybody ever removed the flange on a center axle with good results?  I've heard of this on steam engines (both model and prototype) but not on model diesels.  The other idea I had was decreasing the gauge on the center axle just a little bit.  Anybody tried that?

Keith

HO scale modeling N&W and Union Pacific, somewhere in Missouri between 1940 & 1990!
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Posted by tstage on Thursday, October 2, 2008 2:22 PM

Keith,

You could be right about the newer flanges being shallower.  4% is pretty steep.

Have you tried MUing two locomotives together and running them to see what happens?  It would be interesting to see if both front trucks of the front and rear locomotives derail?

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by Don Gibson on Thursday, October 2, 2008 2:21 PM

...I know 6 axle diesels look and run better on curves greater than 22-26 inches of radius, but my layout isn't going to be changed anytime soon, so that's what I've got.  I can live with the overhang but not with the derailments!  Thanks for any info.

YOU SOUND like  you are using 18"r curves, not 22"r. To get Prototypical looking curves you'll have to to 46"-48" ,and too few of us have that luxery.l

As long as you flirt with the 'laws of Physics' you'll get both derailments & overhang. . You're disecting a 'curve' with a line segment -(straight aligned wheels.  Draw it on paper some time.

BETTER answer is to LIVE WITH IT until you build a larger layout, or accquire 4 axle engines and shorter cars (like the RR's do) for your curves.tures.  You sure you are using 22"r? If you are having 'derailments with 22" radius, better take a closer look at your trackwork.

99% of today's productc are designed to run on 22" radius (exception: some brass, & Walthers 85' passenger cars in their attempt to attract the brass car buyer. Actually, the underframe details is what are limiting it's 'curvature'.

(6 axle engines) require much more compromise to match 18"r.  track. The simplist fix is to remove the center wheelset. Grinding off wheel flanges effectively accomplishes the same thing. Lathes start around $600.

 Since 'switches' are responsible for most track derailments, I'd start with better switches. - assuming you've corrected any wheel/weight issues, such as wheel gauging and centering.

.

 

Don Gibson .............. ________ _______ I I__()____||__| ||||| I / I ((|__|----------| | |||||||||| I ______ I // o--O O O O-----o o OO-------OO ###########################
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Posted by ndbprr on Thursday, October 2, 2008 2:21 PM
If it doesn;t bother you try removing the middle axle on each truck. I had an Atearn U30C years ago that just would not track at all and in furstration I didt hat even though Ihad 30" and larger curves. It cured the problem.  belive it or not very few if any people will notice it. 
  • Member since
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  • From: O'Fallon, MO
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Posted by kbaker329 on Thursday, October 2, 2008 2:14 PM

Tom,

At least 4%.  It is a double tracked figure 8 based off of an Atlas plan.

Keith

HO scale modeling N&W and Union Pacific, somewhere in Missouri between 1940 & 1990!
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Posted by tstage on Thursday, October 2, 2008 2:11 PM

Keith,

How "steep" is steep?

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    March 2008
  • From: O'Fallon, MO
  • 96 posts
Posted by kbaker329 on Thursday, October 2, 2008 2:07 PM

It seems to happen at various places.  I don't have any S-curve situations though.  I do have some steep grades to go along with the curves.  I've wondered if the back two axles are lifting the front axle off of the track.  I've also wondered if the older Athearns and Atlas engines have deeper flanges that keep them from sliding off but can't see any real difference.

Keith

 

HO scale modeling N&W and Union Pacific, somewhere in Missouri between 1940 & 1990!
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Posted by tstage on Thursday, October 2, 2008 1:56 PM

Keith,

I had a friend bring over his Overland 6-axle SD-something to run on my layout.  I have mostly R22" curves, except for a small portion that is R18".  The only place the SD had troubles negotiating the curves was where the straight section of track (separating opposing curves) was shorter than the length of the locomotive.  (This meant that the front and rear trucks were oriented in the same position for a brief moment.)  The front truck raised off the rail slightly then "rerailed" with an audible "clack".

Where exactly are you have the problems on your curves?  The beginning?  The end?  In the middle?

Tom

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    March 2008
  • From: O'Fallon, MO
  • 96 posts
6 axle diesels and tight curves
Posted by kbaker329 on Thursday, October 2, 2008 1:37 PM

I have a question concerning 6 axle diesels and curves under 22" radius.  Most of my Atlas engines and a few of my Athearns handle 18" with no problems.  However, a few others like my new Athearn N&W SD45 and my Southern SD40-2, don't.  Has anybody modified a 6 axle diesel to work better on tight curves, i.e. modifying the trucks to allow more slop, allowing the truck to swing more, etc.  I'm looking for ideas to try.  And please, before the bandwagon starts rolling, I know 6 axle diesels look and run better on curves greater than 22-26 inches of radius, but my layout isn't going to be changed anytime soon, so that's what I've got.  I can live with the overhang but not with the derailments!  Thanks for any info.

Keith Baker

HO scale modeling N&W and Union Pacific, somewhere in Missouri between 1940 & 1990!

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