help with helix

[randyaj]

I am building a second layout and am in the planning stages. I have a 15 by 42 foot space in two rooms. I want to have a point to point layout with as much length as possible; therefore I am considering a two level layout. I am thinking of a helix with a 30" radius and a 2.5% climb, this will give me about 4.75 total inches of seperation, does this seem correct?
Thanks for your input it is greatly appreciated
Randy Johnson
Iowa

[Medina1128]

Are you using any software to design your layout? You can download Right Track free from atlasrr.com, and it will design the helix for you.

[Anonymous]

Randy,

Your figuring appears to be correct. I built a 30" radius helix with a 2% grade and ended up with about 3.75" seperation between railheads. Consider double tracking your helix to get extra staging or a return track. Not much more effort...big benefit.

[selector]

Unless I misunderstand, the separation of your two levels is also dependant on how many complete turns your helix makes before it 'tops'out'. You are essentially correct if you make one complete 'loop', but adding more of a second loop will raise your higher level(s) by that much more. Four and a half inches is not much separation if you will occasionally have to reach into that space to right derailed locos or cars.

[Anonymous]

Crandell,

I believe he was referring to the seperation gained by one turn. Obviously one would want to make severals turns if one wants a decent climb. Mine goes around four times on the upper part to give me 20" between bottom and top decks. It starts at a 4" elevation entering the helix. Yes, it is tight reaching inside to get cars. All helixes of the 30" radius variety share this drawback. It is not too bad because you don't have to reach in very far. My track work is impeccable inside the helix to avoid having to reach in as much as possible (knocking wood).

[Adelie]

I downloaded a helix calculator somewhere, and it claims that using a 30" radius and a 4.75" vertical clearance between the levels will work out to a hair under 2.4-percent on the grade. So, sounds like your calculations are pretty accurate. Go forth and build!

[ndbprr]

circumference is pi x D so 3.14 x 60 = 188.4". 188.4 x 2.5% = 4.71" BUT that is from the top of one surface to the top of the second surface. The clearance will be minus the thicknes of the roadbed. Not to be overlooked.

[selector]

Agreed, Guy, and thanks. I admire those who can build impeccable track, but sure understand why you'd need it in a helix! [tup]

[randyaj]

thanks for all the info, how about a couple more questions? What is a good working distance between levels? and what would you consider the height of the top level off of the ground acceptable?

[selector]

Randy, it depends (don't ya just haaaattte that answer?)[:D]

Do you have a master plan? How long is your layout (I ask this because it will have a bearing on your grade to a next level if you DON'T use a helix)?

As a general rule, you should do your best to design your track plan and benchwork to grant you access to any possible points where you may encounter a derailment, or dirty track, or buggy turnouts. So, depending on your stature, and on your main bench height, you will want a reach to any place on your layout not to exceed 30"...period.

With a bent elbow, and bending over the layout, how carefully can you reach into, say, 6" and replace a loco or rolling stock on the rails there...assuming you'd do that? Judge your overlapping tracks accordingly. As for how high your upper level(s) should be, it depends on helix turn, how much topography you'd like to build, and how long a grade you can build into your topography, keeping it under 2.5%, and still have track space for that upper level.

Don't know if this is being helpful, but I thought I'd point out variables that could determine the outcome.

[sledgehammer]

here is the site for the helix calculator
http://www.railroaddata.com/rrlinks/Detailed/3941.html

[Anonymous]

Randy,

Mock it up and see what you like. I settled on 39" and 59'" for the two decks. My neighbor thinks I don't like him because he will have a hard time seeing onto the top deck....This is a drawback to double deck layouts...Probably the ideal deck height is about 50 inches, somewhere in the middle of my decks. The top may be slightly too high and the bottom will give you the helicopter view of the trains. My spacing is 20" between the railheads. Don't forget I have to get supports, fascia and switch machines for the upper deck as well as lights for the lower deck in that space. I also need to provide an unobstructed view of the bottom deck. If you reduce the spacing then you run into other problems and make other compromises.

Other considerations include: How wide will the decks be??? How will you light the bottom deck etc??? The main reason most of us go double deck is to get the long run, which is a very cool thing. However, it does come at a cost. Depending on the configuration, your space might be an ideal canidate for a mushroom design. Check out Joe Fugate's web site for info on this design if you aren't familiar with it. He has a great DCC clinic going on the general RR forum at the moment. Click on the link in his signature for the site link.

[chateauricher]

QUOTE: Originally posted by randyaj
I am building a second layout and am in the planning stages. I have a 15 by 42 foot space in two rooms. I want to have a point to point layout with as much length as possible; therefore I am considering a two level layout. I am thinking of a helix with a 30" radius and a 2.5% climb, this will give me about 4.75 total inches of seperation, does this seem correct?

I have a couple suggestions for you to consider. (I'm presuming you're working in HO, even though you didn't say what scale you're working in.)

Reduce your grade to 2% and increase the radius to compensate. While a 2.5% grade is ok for a straight line; the effect of a curve makes it seem steeper and your locomotives will have to work harder to pull a string of cars up the hill. To maintain a gain in elevation of 4.75", you'll need a radius of 37.75" (75.5" diameter).

OR

Consider a "no-lix": Like you, I wanted to increase the "real estate available for development", so I planned a two deck layout with a helix. That was until I realised just how much room a helix takes up that cannot be used for anything else. The area taken up by a 30" radius helix is 2827.43 square inches (19.64 square feet) !!! And you can't use it for anything. Your layout will be about 630square feet; of which the helix will gobble up more than 3%.

Benefits of a "no-lix"...

1. much simpler construction (just build a "shelf" along the wall(s) at the appropriate grade and disguise it as a mountain-side);


2. allows you to keep those 19.64sq.ft. as usuable space;


3. allows you to see your train as it climbs/decends to the other level;


4. allows you easy access for maintenance;


5. allows you easy access to retrieve a derailed train (no matter how good you are at laying track and maintaining your trains, derailments will happen);

You can also (as I plan to do) include a passing track part way up your "no-lix" (or go with double tracks with a couple cross-overs).

With a 15x42ft room, theoretically, you could have a change in elevation (with a 2% grade) of about 50.4" (2520" or 210' long run). You wouldn't need to make even one complete cicuit of the room. You could get away with going along a bit more than the length of two walls (15 + 42ft) to get a change in elevation of about 13.68". You will find that a bit tight, so I suggest you go with at least 15" (keck to deck); which means your "no-lix" will require a run of about 62'-6" at 2%.

Hope this helps.

[Anonymous]

A way to add length to your no-lix easily and believably is to place a large mountain at the end of your layout and have the train begin to climb about 6' from the mountain and to climb up around it. You can easily add 10' to the track this way.

Mark in Utah