# Is this Layout Acheivable



## psychotrshman (Jul 19, 2011)

Good afternoon,
I'm a newbie to the model train hobby and I'm still working out the finer points of my first layout (measure twice and cut once was my Dads philosophy). I have an idea for what would be the main focal point of the table / scene and I'm just looking for some guidance on whether this would be possible and how I can figure out the amount of track / space that I will need to acheive this. My first table will be a 4 x 8 sheet of plywood and it will be done in N Scale. Here's the idea: The majority of the train will wind through the country side, a steel yard, and a small city or two. I plan on having a large lake / river in the middle of the table (think tale of two cities style) dividing it into two parts. Now heres the part I'm not sure of, I want to have two helixs, one on each side of the river / lake, and I want the train to go up one side to about 12 tp 14" off the table, cross a wooden truss type bridge over the lake, and then go down the other side in a helix. I think having one helix exposed and on revelaed would be incredible, but I'm not sure how to acheive this, or if its even possible in the space I'm using. Any guidance to reference material or any advice is greatly appreciated. I'm not afraid of doing the research or the leg work to check to see if this can be done, but I just dont know where to look for that information. I have some clearance information from the NMRA that is my starting point, but I'm sure I'll need to know more than just that. Thanks in advance for your time and your help.


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## tjcruiser (Jan 10, 2010)

Use the "Search" tool in the top menu bar of the forum to hunt for "helix" ... you'll likely see several threads / discussions on construction options.

I'll try to find some good example later ...

TJ


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## aionta (Apr 9, 2010)

*new layout idea possible?*

I have seen a few layouts where they divide the layout into different terrains or seasons buy having a plywood divider that is painted with background details.

The division would not have to be in the middle but could be the start of
the mountain range and used to hide the helix.

You could even hide the other helix in a mountain on another part of the layout.

place your major design elements and then see if your track plan can be made to fit. do this on paper and when you get a plan that you like or is close use one of the free track layout designing tools to see what is really possible.

Have fun!

Aaron


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## sstlaure (Oct 12, 2010)

Helix's take up a lot of space. Rather than (2) separate helix's have you considered one helix, but multiple tracks wide so that the train can go up one side of the helix, cross the tracks along the table as you like, loop back to the helix and go down the other side. That's what I'm planning on doing. 

I'll have (2) helix, but one will be inside the other. (both double track - so it will be 4 tracks wide total) The outside 2 tracks will go upgrade and the inside 2 tracks will go downgrade. (check my build thread - I've uploaded some drawings of my future plans)

It takes a bit of planning, but you'll use up less real-estate going this route.


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## RailMix (Apr 4, 2011)

I don't remember when offhand, but there was an article on a train elevator as an alternative to a helix in Model Railroad Planning a few years ago. That would save you some space also.


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## gunrunnerjohn (Nov 10, 2010)

Boy, never thought of having two sets of double tracks in the helix! I'm going to be happy to get my dual-track one working. 

The train elevator is considerably more complicated!


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## psychotrshman (Jul 19, 2011)

I'm kind of attached to two separate helixs, I'm just not sure how to make it work with a reasonable grade. It seems the grade to achieve the correct height each go round would exceed 2 to 3 percent. My assumption is that the helixs would be identical. I could just duplicate the first helix and place it somewhere else. I've seen images of helixs working in other scales, so I know its possible. I'm just curious how you do the calculations and know that the train can pull the climb. I plan on "burying" one helixs inside a mountain, and would hate to end up with a little engine that coukd situation. I'll have an access to the inner mountain, but I'd still hate to have it stuck inside because of lack of power.


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## sstlaure (Oct 12, 2010)

Well....the way to calculate is:

You need sufficient clearance between tracks (check NMRA standards for clearance.)

Circumference of a circle is 2*pi*R
pi= 3.14159
R=radius of the track (lets say 18")

So for a single loop of the helix at 18" radius you're looking at 2*3.14159*18= 113.1"

You're using N-scale so let's say you need to rise 2.5" over the circle so that you have room for roadbed and clearance for the tallest cars.

2.5" rise over 113.1" run is a 2.2% grade (2.5/113.1). If you want to lessen the grade a bit and you have the room you could also make it an oval shape by adding some straights within the helix.

To keep a decent grade on the helix I'm planning I'm looking at 36, 33, 30 and 27" radii for my various tracks. 1.77, 1.93, 2.12, & 2.36% grades respectively. (I'm using 4" clearance for HO.)

There are tons of helix videos on youtube in all scales.


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## haphall (Feb 1, 2011)

Clear as can be, Sst.


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## Massey (Apr 16, 2011)

OK one thing I think you need to consider here is the space. N scale can run a tight curve at 9" radius which is about 18" of track and lets give an extra inch for clearance which brings us to a tight helix of 20" 12" radius would be a more comfortable place to go and it would be less stress on the engines in both drag and incline. Now you have high demands or goals for a standard 4X8 but that same 4X8 sheed can be cut a couple of times giving you the same 32 square feet but in a more practical and longer run. If you were to cut the 4x8 into 4 2' sections and make a C or a dog bone out of them you could also create a "modular" layout that can be set up in many different ways like MR did last year for their beer run layout, you will be able to better get what you want including a helix that does not stress the engines, your 2 cities, and plenty of area to switch, have a yard and all inportant have some fun. 

If the 4x8 is the only option you have or only one you will consider I would really think twice about he helix, but you could always do an incline to a upper level (one city) that doubles back to the incline using double track or a tear drop shape and have the mountains (under the city) and the other city inside the loop that does the incline. You could get tunels, mountains and your cities all in one layout without the helix.

Massey


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## flyboy2610 (Jan 20, 2010)

If you do have one helix hidden, be sure to plan your scenery so you can get to the backside of it. As sure as anything, that is where your train will derail.
Murphy lives on model railroads, and he practices law any chance he gets!
(One of the store fronts on my layout will be for "Murphy's Law Office. )


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