Helix const.

[Anonymous]

I am going to make or buy a ready made helix and want to know what is the minimum radis I can use for a 2 track N scale?? I would like to keep it as small as possible as I have miniimum space for me layout of which I am planning.......Will wait for comments...........

Thanks David Hanlin Manitoba Canada

[Anonymous]

What is the widest your track can be? What is the maximum radius it can be? If a small radius, then the outer radius is your up track (less grade) and your inner track the down track (greater grade).

If you give us your maximum radius you can have, then it is easier to say whether it is realistic or not. And what will be your highest rolling stock going through it (need this for amount of seperation between decks.

[Anonymous]

Yes my max radis will be approx 14.5 inches

Thank you for responding also give me som ideas of how to construct this thing if you can

David Hanlin

[nfmisso]

Let's say you need 2" rail top to rail top. With a 2% grade, you need 100" of run. DIvide 100 by 2(pi) and you get:16" radius. You may need to construct an oval helix instead of a round one.

For construction technique, I recommend threaded rods with thin metal plates between them, and nuts on each side of the plates to adjust the height. You'll need about 36 threaded rods for this.

[Anonymous]

Here is a link for you with some pictures; the pics will give you some different ideas on how to build one.

http://forum.atlasrr.com/topic.asp?TOPIC_ID=32175

[Anonymous]

QUOTE: Originally posted by nfmisso

Let's say you need 2" rail top to rail top. With a 2% grade, you need 100" of run. DIvide 100 by 2(pi) and you get:16" radius. You may need to construct an oval helix instead of a round one.

It should be pointed out that the overall total thickness of the roadbed you choose to construct is of prime importance when calculating effective helix grades, and therefore effective radius you'll need.
I believe conventional N scale vertical clearance is about 1 5/8". Therefore, if you use N scale cork roadbed ( 3/16" thick )over ,let's say, 1/2" plywood...you get 11/16" of extra rise required to achieve your clearance. This is now 2 5/16"...so on a 100" run, the grade is 2.3 %.
If you use the cork + 3/4" plywood instead of 1/2", the grade for that same 100" run becomes 2.6%.

Clearance side-to-side :
Do you use long modern freight cars [ 80 ft.], or full length passenger cars ?
This may also be a factor, if you might ever have a train parked on one track of the helix while another one is passing it.
regards
Mike

[Anonymous]

You don't need roadbed in a helix. Noise on roadbed isn't the issue it has been portrayed to be. However, noise is a helix is a good thing. I don't know how many guys I have seen walk over to a helix and put their ear to the mountain to see if the train was still running. Every helix I have seen in person hasn't had roadbed.