Author Topic: Helix advice  (Read 1529 times)

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crrcoal

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Helix advice
« on: April 18, 2014, 07:39:43 PM »
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I'm thinking of adding a 2nd shelf. I have a 25" x 25" area to put a single track helix. Largest rolling stock would be coal hoppers maybe a 4750 covered hopper. Largest motive power would be the SD70ACe. While the layout itself will be code 55 I was thinking of using unitrack for the helix. Appreciate any help/advice! Thank you.

mmagliaro

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Re: Helix advice
« Reply #1 on: April 18, 2014, 07:48:30 PM »
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I like the idea of using Unitrak.  It may have lots of joints, but so what?  Make sure the joints are smooth.  Even solder and dress them with a file if you have to.  But the curve will be rock solid with uniform radius and gauge and that will make it work.

I do have a concern about the space you are putting this in.  25" means that at best you will have 12" radius curves.  Long wheelbase engines will make it, but it's asking for trouble.  And the longer the train you pull up that helix, the more trouble you will have with derailments.   Is there any way you can press out into the room more and get your radius wider?  A helix is no place to skimp on using gentle grades and broad curves.  Can you get more like 36", so you can have a 17" or 18" radius?


Scottl

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Re: Helix advice
« Reply #2 on: April 18, 2014, 07:53:49 PM »
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I would echo that concern, 12" radius is pretty tight for six-axle locomotives like the SD70ACe.  I'm aiming for 16" minimum on my layout and I'll be using similar locomotives.

Flagler

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Re: Helix advice
« Reply #3 on: April 18, 2014, 08:12:31 PM »
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I wish Kato would make a Helix

Baronjutter

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Re: Helix advice
« Reply #4 on: April 18, 2014, 08:24:35 PM »
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12" is wayyy too small for a helix, or at least a helix that will work.  Your big 6 axles will most likely make it, but with the grade you'll need you'll be lucky to pull more than a few cars behind.  With a helix bigger is always better and safer.  It is technically possible to make a 12" radius helix but you will be severely limiting how long your trains can be and potentially introducing some serious reliability risks.

I know Mr. Fifer recently made a helix out of unitrack that works quite well, but I'm pretty sure it's bigger than 12" radius.  I think he's got a layout thread somewhere in here but he had a whole series of updates and videos about his unitrack helix.

glakedylan

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Re: Helix advice
« Reply #5 on: April 18, 2014, 09:56:46 PM »
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actually Mr Fifer's helix is using 11.3 and 10" unitrak if I recall correctly
you may need to double or triple head or add helper
and keep trains to 10-12 cars but he has done it and done it well.


gary
"...that each may live for all,
and all may care for each..."

Baronjutter

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Re: Helix advice
« Reply #6 on: April 18, 2014, 10:02:13 PM »
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/>
Looks like Mike's helix really is so compact!  If you don't run very long trains it looks like it should work ok.

ednadolski

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Re: Helix advice
« Reply #7 on: April 18, 2014, 10:18:29 PM »
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Honestly a 12" radius sounds too small.  The circumference is 75" which is a 2.7% grade to get a 2" rise in one revolution.  From that you also have to subtract the thickness of the roadbed and subroadbed (how thick is Unitrak roadbed?), plus you need some extra vertical clearance just to be able to get your hand in there.

Going upgrade is an issue for how much the locos can pull, but don't forget that whatever goes up must eventually also come back down.  Going downgrade puts truck-mounted couplers into considerable compression and thus will have a greater tendency to derail, esp. as your trains get longer. 

You can keep the trains short, but is that really appropriate for multiple SD70Aces?

HTH,
Ed

ednadolski

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Re: Helix advice
« Reply #8 on: April 18, 2014, 10:24:12 PM »
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/>
Looks like Mike's helix really is so compact!  If you don't run very long trains it looks like it should work ok.

Is that masonite?   Yikes, just don't bump into it...  :facepalm:

For the same vertical thickness, you could use a good grade of 1/2 plywood without the Unitrak, and it would be a lot more sturdy.

Ed

CodyO

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Re: Helix advice
« Reply #9 on: April 18, 2014, 11:42:08 PM »
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Go unitrack!
I have a double track super elevated helix installed no problems whatsoever would recommend it to anyone
Modeling the Pennsylvania Middle Division in late 1954
             Nothing Will Stop The US Air Force

peteski

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Re: Helix advice
« Reply #10 on: April 19, 2014, 01:03:13 AM »
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Go unitrack!
I have a double track super elevated helix installed no problems whatsoever would recommend it to anyone

Ok, but what is the radius?
--- Peteski de Snarkski
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CodyO

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Re: Helix advice
« Reply #11 on: April 19, 2014, 10:18:27 AM »
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It leads from staging up to main deck

36" diameter helix
Outside curve is 16 3/8" and inside is 15"
We custom built this helix and another that will go on top of this one when there finished.
The unitrack provides great reliability and was a easier to install then flex,just snap together and push down the top of the helix and your done
Modeling the Pennsylvania Middle Division in late 1954
             Nothing Will Stop The US Air Force

crrcoal

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Re: Helix advice
« Reply #12 on: April 19, 2014, 12:13:07 PM »
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Here's how the room looks


My initial thoughts were to put the helix down near the closest door hence the 24" x24". (No, going inside the closest in not an option. Over by the doorway wouldn't really work either. When I had my HO layout I had a 24" shelf. It was a pain walking into the room as I ALWAYS caught the corner of the shelf.

So I can go 30" x 30" but that would fit in the upper left corner. That lets the air out of the sails because I was looking for a long run from yard up the branch.

Open to suggestions!!

Baronjutter

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Re: Helix advice
« Reply #13 on: April 19, 2014, 12:32:01 PM »
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You could have the helix in that corner but totally under the layout, then have the track go towards the closest but down, then loop down on its self.  A nolix leading to the helix.

eric220

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Re: Helix advice
« Reply #14 on: April 19, 2014, 01:34:49 PM »
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Why can't you do a 36" helix at the end of the 16" wide section by the door?  That only sticks out into the room another foot and a half, and leaves four feet between the helix and the edge of the benchwork along the 9.6' wall.  Of course, it becomes a problem if you're trying to build a yard on the lower level.  Simple solution: (depending on what's already built versus int the design phase) but it on the upper level!
-Eric

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