Author Topic: HOn3 trackage design criteria  (Read 543 times)

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Cajonpassfan

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HOn3 trackage design criteria
« on: July 29, 2021, 05:57:50 PM »
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Hello narrow gauge aficionados, I need some validation here please. My primary scale is N (see my ATSF LA Division thread in the Layout section if you care to) but for now, I’m heavily involved in designing and helping build a very large HO layout for a good friend.

One 28’ long isle, with track and scenery on three sides, is dedicated to what we call “narrow gauge country”. It will be a freelanced, RGS/D&RGW-ish line, connecting with a standard gauge/dual gauge branch line at about 46” elevation and climbing up to about 62” at its mountain terminus. Another short branch will continue climbing up from there to a series of mines at about 72-75” elevation. The floor there will be raised about a foot.

Equipment used will be mostly Blackstone, but there is some brass as well, including a couple of Mudhens. We’ve set the minimum radius at 28” and maximum grade at 2.6%, with 3% on the mine branch where trains will be quite short. Grades on curves will be compensated. My question is this: do these criteria sound reasonable? I’d like steeper grades, but I’m told that would be a mistake?

For orientation, I’m attaching a bird’s eye view showing the current state of the partially completed “narrow gauge county” isle. The turnback curve on the bottom is mocked up at 28”r., and the terminus will be above the (hidden) staging yard return loop beyond the trash can. All other trackage shown will be hidden below scenery.

Colorado narrow gauge is my “other” love, so this project gives me a chance to venture into it without abandoning my first love, mainline ATSF 😎

Knowledgeable feedback appreciated,
Otto


« Last Edit: July 29, 2021, 05:59:48 PM by Cajonpassfan »

Mike C

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Re: HOn3 trackage design criteria
« Reply #1 on: July 29, 2021, 08:00:25 PM »
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 Yes very reasonable . I run a mix of Blackstone and brass . I have 18 " radius curves and so far Westside K 27 and K 37 will work fine with min. mods . So I believe any Brass 2-8-2 locos will run fine on 22" curves , They MIGHT need mods . but it should be easy ones .......Mike

OOPS ! 28" is more than adequate .....Mike
« Last Edit: July 29, 2021, 08:02:49 PM by Mike C »

Santa Fe Guy

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Re: HOn3 trackage design criteria
« Reply #2 on: July 29, 2021, 08:24:09 PM »
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 Hi Otto.
These sound good to me, I know we have talked before.
Keep these grades, anything greater will cause issues. My friend who is building a new RGS layout tried a Blackstone loco on a steeper than 3% grade with 6b cars and a caboose and it just stalled. Sure you could double head but.
Layout looks massive.
Have fun.
Rod.
Santafesd40.blogspot.com

Dave V

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Re: HOn3 trackage design criteria
« Reply #3 on: July 29, 2021, 08:41:23 PM »
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28" is plenty generous!  I've seen the Uintah mallets take much tighter turns than that in HOn3.  On my RGS I have two 18" radius sections (very short, but there) with mostly 19-21" radius elsewhere and it takes everything up to and including K-27s.

Now the bad news...  Based on my experience with the club layout, 3% is absolutely a hard maximum if you plan on running any Blackstone C-19s.  I love my Blackstone C-19s and I damn near have them all, but I also have no grades on my layout.  The tight curves are really the limfac for my C-19s.  Our club layout has something less than 3% on the end loops with roughly 20" radius curves and you can expect Blackstone C-19 driver slippage with more than 3 or 4 cars behind.  OTOH, Blackstone K-27s will storm up those curved grades like they're not even there.

Then again you may decide that that's OK...there's operational interest involved when double-heading becomes truly necessary.  Also, if you don't plan on using Blackstone C-19s, then no worries about 3%.

« Last Edit: July 29, 2021, 09:02:51 PM by Dave V »

Cajonpassfan

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Re: HOn3 trackage design criteria
« Reply #4 on: July 30, 2021, 10:51:48 AM »
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Mike, Rod, Dave, THANk YOU, that’s very helpful.
Even with the amount of space we have, there are still some challenges trying to squeeze everything in place and make it look and operate correctly. This gives me to confidence to charge on 8)
Thanks again, Otto


Oh, one more question: how long do the sidings need to be to accommodate say 16 cars plus two engines? Seven feet OK?
« Last Edit: July 30, 2021, 10:56:01 AM by Cajonpassfan »

Dave V

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Re: HOn3 trackage design criteria
« Reply #5 on: July 30, 2021, 01:50:51 PM »
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Mike, Rod, Dave, THANk YOU, that’s very helpful.
Even with the amount of space we have, there are still some challenges trying to squeeze everything in place and make it look and operate correctly. This gives me to confidence to charge on 8)
Thanks again, Otto


Oh, one more question: how long do the sidings need to be to accommodate say 16 cars plus two engines? Seven feet OK?

Otto, only one way to answer that, LOL.  I don't run trains that long so I wouldn't know.

You can either math it out by figuring narrow gauge cars at 30 scale feet plus some extra for the coupling distance or you can make up a train and grab a yardstick.  I'd do the latter.

Don't forget to consider the distance back from the turnout so you don't foul the adjacent track.  The plow on a K-27 can stick waaaaaaaaaay out.   :scared:
« Last Edit: July 30, 2021, 01:54:17 PM by Dave V »

Cajonpassfan

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Re: HOn3 trackage design criteria
« Reply #6 on: July 30, 2021, 05:11:52 PM »
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Well, LOL, why didn’t I think of that?! Could be on account I don’t yet have access to the rolling stock…
But there is a third way. One could measure an engine and eight cars and multiply by two?
Thanks!
Otto

Santa Fe Guy

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Re: HOn3 trackage design criteria
« Reply #7 on: July 30, 2021, 08:45:59 PM »
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Yep I run K27 or C19 in front of six cars plus a caboose with no grades.
Don't forget Blackstone Cabooses have wheel wipers that add some drag.
I make my sidings to accommodate these lengths with as much room to move so opposing trains can pass with plenty of clearance at each end due to the overhang of cars.
I also have slightly wider track centers for large fingers and apperance, they vary from 1 3/4 inches to 2 inch.
Rod.
Santafesd40.blogspot.com

Cajonpassfan

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Re: HOn3 trackage design criteria
« Reply #8 on: August 07, 2021, 08:11:16 PM »
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Okay,  I made some more progress, installed the 28” radius return curve (per positive feedback here) and some moře benchwork, see pic. But now I need some more input please: we were planning to do a bunch of dual gauge trackage in the “narrow gauge country” and we have a number of dual gauge turnouts (Lambert?).

But, a friend advises not to use them as he’s having all kinds of derailment issues with them and regrets using them on his own layout.
Dang. That would be a bummer and we’d have to rethink the track plan significantly.

Does anyone here have personal experience with these and what are your thoughts?
Knowledgeable feedback much appreciated!
Thanks, Otto

Santa Fe Guy

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Re: HOn3 trackage design criteria
« Reply #9 on: August 09, 2021, 08:11:30 PM »
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 Cannot help you there, none of my friends run that brand and no dual gauge track.
If your friend joined the HOn3 Narrow Gauge Facebook group they might have some suggestions.
They are a good bunch and I have learnt a lot from being involved.
Rod.
Santafesd40.blogspot.com

Cajonpassfan

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Re: HOn3 trackage design criteria
« Reply #10 on: August 10, 2021, 12:35:44 PM »
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Thanks Rod, great advice. Maybe I’ll join, if they have me… :D
Your progress looks good!
Otto