Helix and Grades

[nfmisso]

First 1/2" is bit thin if you are having only four supports per full circle (eight rods). I would suggest laminating 3/8" thick, with the joints considerably offset.

1. Make 1/4 circles and splice.

2. The thin sheet metal will bend to match the grade.

3. see above.

[Anonymous]

In constructing a helix with 1/2 plywood as roadbed and threaded rods to support the structure I have several questions. Pehaps someone could answer them.
1-if plywood is sold in 4'X8' sheets and cutting "donuts" to be opened and connected to make the spiral, how do you cut roadbed with internal radius greater than 48"? would you just make multiple segments and splice them together?
2-using threaded ros to support the structure with nut and washers seems to allow a short section of roadbed to be flattened off the grade. Is this a problem? if so how do you prevent it from occurring?
3-What do you use to splice the sections together to be strong and minimize encrouchment on clearance of the lower level?

[turbine682]

Dwayne,

Really cool idea using the "Ready-Rod". One of these days, I'll need to construct a helix for an O-gauge layout.

I agree that you should document your method and submit it to MR. Eveyone else submits stuff - also, look at the previously mentioned "ready to implement" helix from some company.

Good luck
--Ed

[gerryleone]

Dwayne -- This "ready rod" is a GREAT idea, not only for helixes (helices?) but for other areas of the layout that may need vertical fine tuning. And I can see now: not only can you adjust the grade, you can easily adjust the side-to-side level-ness of the roadbed.

You should consider turning this idea into an article for Model Railroder!

-Gerry

[Anonymous]

Dwayne,
Appreciate the advice, the threaded rod is available in Australia, so I will venture down this track ( pardon the pun )

Cheers Mate

[Anonymous]

Les,

I just constructed a helix. The above suggestions for grades and radii will support you in those areas. But for the actual physical constructruction, forget the notched wood and used continuously threaded rod instead. Here in the Canadian construction industry we call it ready-rod. It's like a ten foot 3/8" bolt that can be cut to length.

I mounted the lenghts of ready-rod to support the inside and outside radii of the helix in four locations around its circumference. Then I set the plywood subroadbed (like a giant spring with roadbead and track already mounted) into the eight rods. I then cut several pieces of thin sheet metal into supports that would fit between the two rods in each support location. Using nuts threaded down the rods I was able to custom adjust the elevation of the sub-roadbed at each rod location.

I hope this helps - a picture would be worth a thousand words - but alas I can only type.

Later, Dwayne A.

[Anonymous]

Les,

I once spoke with a fellow who built several and he said the secret was to cut the vertical supports with notches all at the same time using a table saw, that way they all came out identical. Then you place them evenly around the circle and the track climbs at a very steady grade.

I haven't built my first helix yet, so let me know how it goes.

Good Luck - Ed

[Anonymous]

Chad;

The Track Planning for Realistic Operation book by John Armstrong would be a great help. At page 48 there is a chart showing track centers for curves. Grades and the effects on pulling capacity are shown at page 49.

I have a double track helix with spacing sufficient to run 89 foot cars on both tracks with a 2 to 2.25% grade. The track centers are 20 scale feet in HO and it is 4.5 turns.

As mentioned to Les, there is a kit advertised in Model Railroader.

Good luck,

Mark

[Anonymous]

I am working with HO scale and have a similar question as Les, I am planning a helix that will support dual tracks. On the main line we use a spacing of 2.5” center to center. What type of spacing should we use on the Helix to allow two trains to pass each other.

Cmc

[Anonymous]

Les,

There are a couple of excellent books you should review: Track Planning for Realistic Operation and Creative Layout Design, both by Kalmbach. They are a great resource. If you can't find them I would be pleased to mail/fax the relevant pages to you. An earlier issue of Model Railroad Planning also had a good article on helix building and design. You may also try going to the Model Railroader index and typing in helix. There are several different articles that discuss the helix. Woodland Scenics also offers a ready made system in several grades.

Additionally, you may wi***o check out the latest two issues of Model Railroader as there is a helix kit available. Try www.trainstyles.com

Hope the foregoing is helpful.

Mark

[Anonymous]

Hi, I am constructing a new layout and would like any and all information on the best way to build grades and construct a helix
Appreciate any suggestions

Regards
Les Johnston
Tasmania Australia