Helix question

[Big_Boy_4005]

Big Girl watched the entire construction process, but I seriously doubt that we will be getting married any time soon. She thinks the helix is too cool to be covered up, but I will be hanging a backdrop on it. The compromise is that I will be building a 12" platform in the aisle making the top of the backdrop only 5' high, so she will be able to look down into the "volcano".[swg]

[FJ and G]

aha, not notched risers like some recommend but spacers, individually between each loop. And 22.5 deg. Thanks for answering the questions. And, you're right about the sawzall bouncing around. I've played around with it enough now that I can do some mean cuts.

Thanks!!

BTW, if you ever get remarried, you can use your helix for the frame of a wedding cake and have a dancer pop out the middle. :-)

dav

[Big_Boy_4005]

First of all Dave I CAN"T LIVE WITHOUT MY JIGSAW. I invested in a good one a long time ago. Bosch is one of the best you can get. I haven't checked prices lately, but they should be around $150. There are plenty of less expensive ones out there. The problem with a sawzall is that it has that small foot, and will want to bounce all over the place.

Back to the helix, which by the way, can never be discussed too much.[swg]

Starting at the bottom, since you are going the elongated route, maybe a hexagon would do the job for you. The straight segments can be fairly narrow, and since the curve is fairly small, you may be able to get under the roadbed with 2 well placed pieces of framework. I actually did the layout and planning on the concrete floor with a marker.

As I was building it I used 2 ladders, and climbed over, but after about the fourth turn, I started crawling under. It's a bit of a squeeze since there is only about 20" down there.

For me, it was just as easy to cut all of the frames at 22.5 degrees, one setting on the saw, and 3 different length pieces. It looks fancy but it isn't that bad.

I'm not sure where you think there are notched risers. Some of the risers have cross members spanning between them on one of the turns of the helix. This was necessary where the double track stopped and the the single track continued. The problem was that there wasn't enough room for a riser between the 2 tracks, but most of the risers are simple spacers. In my case they are 7 1/4" and 2 layers of 3/8" plywood for a total of 8" height per loop. Six turns at 8" per turn makes 48" total rise.

One thing that was handy in all this was the track gained 1" in height per segment of benchwork. This was only needed on the first loop, because after the grade was established it was simply a matter of placing spacers.

Hope all of this helps, and it is my pleasure to go into detail for you.

[FJ and G]

Elliot,

I feel bad bringing this topic up to the top so much but I've been downloading and trying to study the construction you used on your helix, which, incidentally, I like better than most I've seen.

It appears that the base of your helix was designed in an octegon (8 sided like a stop sign) shape). Since mine will have some straights it will resemble a squashed octagon.

How do you get inside of it? Do you crawl underneath? Perhaps 24 inches of clearance?

Also, it appears that you can easily make square boxes of wood for four of the side and for the other four sides, the boxes would have to be trapezoid in shape, cut at 45 degree angles.

Secondly, the notched verical risers that support the curved track supporting pieces. Are those vertical risers one piece or did you add a short riser between each level of the helix. Appears you can do either way.

I really like the base of your helix, as it easily allows you to add risers and it appears to be stable and allow crawl space.

Again, I apologize for working this topic to death but I plan to begin work this weekend if not sooner.

My jigsaw broke so I'll be using the table saw, chop saw, and for curves, will use the sawzall. Will hold it together with drywall screws.

Thanks for indulging me.

Dav

[Anonymous]

Cool web site links, Dave! Thanks!

Tony

[FJ and G]

Tony,

I've been searching the web looking at a variety of helixes for model trains, roller coasters and even real railroads, and came up with some really really cool websites I thought I'd share with you all.

Interestingly, every helix looks a bit different; taking on the personality of its creator.

Wild roller coaster train ride helix:

http://www.ridezone.com/rides/coasters/talon/talon20010202/

But “The Beast” helix is even better!

http://www.thrillride.com/SpecialFeatures/Beast/beast.html

And this ride actually looks like a train:

http://www.coastersandmore.de/rides/coaster04/coaster04maine.shtml

Threaded rod helix that goes around a fellow’s HVAC!!!!!
He had furnace problems & had to dismantle the whole deal!

http://home.ix.netcom.com/~elclip/id3.html

Most elaborate model train helix ever built w/reverse loop—scroll down to last 2 photos:

http://users.rcn.com/weyand/pocadiv/pocahontasa.htm

Real railroad helixes can be found here:

http://www.steamlocomotive.com/model/trackage.html

[Anonymous]

I'm somewhat of a roller coaster freak. I've got to lose weight if I want to particpate in this past time again, just another reason to lose wieght.

In any event, Space Mountain's only distinction is that it is always ridden in the dark. The cars actually don't go that fast, so, from a fanatic's standpoint, it's actually pretty tame.

I rode the Incredible Hulk roller coaster the last time I was at Universal Studios in Florida. On this ride, you start up the lift hill normally. Then, to simulate the ru***hat Bruce Banner gets changing into the Hulk, you are accelerated & literally shot out of the lift hill by a series of powerful electric motors. These things have the power to accelerate a car from 0 to 40 in 2 seconds! After that, you go through 9 separate inversions. Too cool!

Tony

Tony

[FJ and G]

Forrest,

I believe the most famous in N. America is up in the Canadian Rockies; CP, I think. The Swiss have the most famous, however, and they soon will be designing a high speed route thru the Alps (isn't it nice that at least some countries are planning major rail construction! I still think a line between Seattle and Anchorage or along the AlCan Highway would be pretty cool.

Reg. weight and stringlining, I may need to weigh some of my long but extremely lightweight and fragile Weaver cars, as they are prime stringlining candidates, being long and light.

I don't know about WP having a huge helix but if you count horseshoe curves as one loop of a helix, I guess you would have an inside out helix.

An outside in helix would be a track circling a mountain, of which I believe there was one, the Mt. Tamuleous (spelling????) near San Francisco, a narrow gauge RR that had the distinction of being called "The Most Crooked Railroad in the World," crooked meaning curvy, not as in theivery.

Space Mountain, a ride that I guess you could classify as a helix railroad, at Disneyland, Anaheim would be a true helix. I recall riding it back in the 70s.

dav

[fjerome]

dave, speaking as a person with recent stringlining combat experience, i suggest that you order your consists very carefuilly. i have added weight to all of my baggage cars to prevent this ugly phenomenon. most of my baggage cars were a pound or more lighter than the other cars in their set.

speaking of real railroading, didn't the WP have a huge one level helix somewhere on their tracks. i will have to figure out where i saw this.

[FJ and G]

Bob,

I never woulda thought of it but it makes sense. I know this to be the case with real railroads on El Cajon's hairpin curve before they straightened it. A lot of brain horsepower pulling here.

dav

[lionelsoni]

You actually may want to use a negative superelevation (subelevation?), that is, tilt the track to the outside, to avoid "clothesline" derailment.

[FJ and G]

027 a bit extreme, Elliot, but 042 with Tony's straightaways sounds like a nice compromise.

The one very slight drawback of combining straights with curves is that if you are under conventional power (nonspeedcontrol) then you will have to carefully monitor the throttle or the train will speed up and slow down; which leads to another question, do you bank or superelevate the curves within a helix to reduce the likelihood of a helix derailment?

It is very interesting how some folks hide their helix inside a mountain and others proudly display their helix. Which Elliot, will yours be?

[Anonymous]

Dave:

Just remember, the perimieter of an oval is the length of the straights plus the perimeter of a circle of the diameter used.

I wish I could take credit for this idea, but it's yet another one I've read about on the forums.

Tony

[Big_Boy_4005]

Right Dave, The Pi x D portion will give you the curve length, then add in as much straight track as you want, for a total length of run per loop. That will bring the grade down and give you some flefibility. If you wanted to go to the extreme, you could use 027 with long straights, and still keep the grade down.

People always marvel at a helix, so you may not want to cover it up with any scenery.[swg]

[FJ and G]

Thanks guys, for the formulas & stuff. BTW, the formula uses Pi and if it is an oval with straights, the formula would need to be modified to take the straights into account.

Tony's suggestion for an oval with straights is awesome. Great idea!

I'm busy cutting and pasting these ideas into Word documents.

Yes, I recall our discussions on helixes, that was the planning stage; now I'm actually building it; and building is MUCh different than planning.

If I recall, our discussions Tony, we spoke about the "Nolix" movement, which is an angry group of scale modelers who protest helixes by building long ramps to gain elevation behind the layout instead of helixes.

Then there are the nasties who model "ruptured helixes." Instead of nice symettrical helixes, these creepy folks, bulge out one or more ends of their helixes and actually scenic the bulge. Sort of like designing a helix with a tumor sticking out one end. It makes a portion of your helix functional.

There are probably countless other crazy ideas that folks dream up. What an interesting world of model trains!

I'd like to decorate my helix with a bunch of giant gatemen that I have from Forrest's junk pile, so that as the train ascends or descends the helix, the gateman comes out to greet the train at each loop. That would be kinda wild.

dav

[daan]

The swiss mountain railways (Furka oberalp bahn, raetische bahn, etc) also have single loops. That is narrow gauge rack railway track, so angels and curves ar very tight.

[Big_Boy_4005]

Tony is absolutely correct, adding straight sections to any diameter circle, is the same as increasing the diameter, just that you are only doing it in one direction instead of two.

There are a lot of examples of single turn loops around the world. The real railroads want to keep their grade down too.[swg]

[Big_Boy_4005]

Dave, I whipped up a little table for common circle diameters, and different height gains. The formula is pretty simple: height gain / (Pi x Diameter). My Helix turns out to be 2.12%, that's 8"/ (Pi x 120"). The helix is 10 feet across.[swg]

The numbers are acceptable for 054 up to 7" height gain. The 063 numbers are good up to 8".

Remember, height gain includes roadbed and track!!!! Make sure there is enough clearance for your trains.

[Anonymous]

Oh, and David? Regarding helixes in real railroading...

We (you & I & others) had a thread on OGR before the upgrade where we talked about & identified what were essentially one-level helixes in the real world. As I recall, there's one in the Canadian Rockies that CN uses to lower the tracks 50 feet (it has a diameter or radius of one mile, I believe) and so bypass having to climb a mountain.

There's also one on the Darjeeling railroad in India at the top of a mountain. The railroad climbs this mountain using a series of switchbacks, then, when it gets to the top, uses a loop to start its descent down the other side.

A number of other folks pointed out one or two other examples.

No, there are no multiple level helixes like are sometimes used by modelers, but the real guys use 'em when they have to!

Tony

[Anonymous]

Dave:

You can also decrease the grade without increasing the radius by making it an oval shape instead of a circular shape. That is, add, say 3' to a side. In that case, the total length of one circuit becomes

{(Pi * 54) + 72 = 242

With a 6" rise, that gives you a 2.5% grade.

It seems to me that the best way to construct a helix is with wooden spacers between levels. It's real easy to make sure that they're all the same length, so you end up with even spacing. You could bore a hole through the spacers & put threaded rods through them. Then the rods can be used for suppot & to tighten up the whole assembly.

The threaded rod wouldn't be absolutely necessary, though.

Tony

[FJ and G]

Thanks; 054 sounds good. Too bad there are no helixes in real railroading. At 054, with that much space, would look good with scenery. perhaps an inside-out open pit mine? Hmmmmmm?!~

[Big_Boy_4005]

Good morning Dave, unfortunately you can't simply pick your grade out of the air. Grade is tied to radius and verticle spacing. Using your 042 and multiplying by Pi, we get about 140" run per loop. Each loop needs to gain about 6" in height in order to give you the head space to run traditional O gauge trains. Scale takes even more clearance.

Doing the math, an 042 helix with 6" spacing comes out to about 4.2%. Move up to 054, and the grade comes down to 3.5%. If you need more head space for larger cars, the grades get steeper again. Keep in mind 4% should be your max, because you want the engine to be able to pull the cars up.

Wood is just handy for me, I cut spacers all the same size, and I'm off to the races. The threaded rods are small and pretty, but I don't just have them laying around.

I built what I needed, part double, and the rest single. The decision is based on layout design, and nothing more. I've seen a 4 track helix in HO before.[swg]

[FJ and G]

Forrest,

I crawled around the HVAC room last night with sections of track, measuring and pondering. I think you are right; the HVAC room may get too crowded for a helix, so now I'm seriously considering a helix in my daughter's bedroom at the opposite end of the basement and instead of helix in the HVAC room, simple return loops for theupper and lower shelves.

So, now I have to start the whole thought process over again!

If I place a helix in her bedroom, I don't want it to be too big for obvious reasons. (Actually, the bedroom is about 19X19 & she's going to college this year and may not use the room that often).

I was thinking 042 helix; because that's the size all my trains can negotiate.

Which leads to more questions!

1. At 042, what grade would you suggest; 2%?

2. Elliot used wood for his vertical supports. I've heard tell that some use long threaded screws. Pros & cons?

3. Elliot uses a double track helix. What are the pros and cons of single vs. double tracked helix?

Thanks.

Dave.

[daan]

To get gradient right in a helix, you could use threaded wire and nuts (don't know if that's the correct name for it). Inside and outside the helix you locate one, and by turning the nuts you can finetune the level you need to have.

[fjerome]

"The challenges for me will be accessibility and easy-to-remove helix, to get to the various HVAC elements if repairs ever become necessary. it definitely will be one of a kind."

geez, dave, you don't set your sights low, do you? [:D]

[FJ and G]

Thanks, Elliot,

I see the diagrams now!

[Big_Boy_4005]

Dave you don't need the wye near the helix if this is the top or bottom level. The wye can be a part of the main layout, like the first diagram. I suppose the "I don't know" could be used for a middle level if you didn't have room for the wye.

[FJ and G]

OK, back from lunch. Ate lots of onions so pardon my bad breath.

Anyway, where was I? Oh, yes, I'll be busting thru the drywall of the HVAC where the helix will be located. As the train exits thru the wall, it crosses a great chasm, which is my 7 ft wide hallway. Instead of a bridge, I'm building a removable extension of the layout that will be scenicked as desert.

I may design a portal on the wall where the train exits/enters. Actually, based on the above Elliot diagram, 2 portals thru the wall, because once inside the HVAC, there's no room for the Wye split.

Thanks for all of your great suggestions. Sorry for the bad smell but it's even worse when I put raw garlic on my sardines.

Dave V.

[Big_Boy_4005]

OK Dave, while you were at lunch I drew this.



The top two are useful, the bottom one, WELL....................[swg]