I’ve been reading about people having a helix. What is it and it’s purpose?
Tom
the helix is a subroad bed that spirals upward (or downward) to put trains on different levels of the layout…have you ever been in a parking garage?..it sort of works like that…you go up and up onto each level until you reach tthe top then spiral your way back down to the street level again when you leave the parking garage…they are complicated to build because you need at least 3 1/2" ceiling so that the trains can fit through each turn in the helix spiral…if i were to use one, i think i’d use the premade type that are on the market…Chuck[:D]
A number of us have layouts with 2 or more levels of operation. In order to transition the trains from one level to the other requires a setup which allows the trains to either climb or return down a reasonable grade of track. Usually this is done in a section of spiraling track, commonly referred to as a helix. Usually one layer of circle on top of its self until. the rate of climb is really dependent upon what you are pulling and how much equipment you want to use to get it up there. Usually, a 2 1/2 to 3 percent grade is about as steep of a climb a standard engine and maybe 10 cars can take without helper service.
Helix’s do take up a lot of space and when completed look like a coil spring. the last one i helped build was an 8’ x 8’ and it went up 5 levels to get cover a 30" clearance.
Normally these things are covered with plaster on the outside to give the illusion of a mountain.
Hope this helps.
There is a lot of controversy regarding helixes today. originally viewed as a way to double the size of a railroad space considerations and the time a train is out of sight have somewhat diminished the enthusiasm for them. generally what happens also is the operator gets concerned his train might stall on the grade and keeps bumping up the controller so a train rockets out of hiding at very fast speeds when it reaches the top level. The other problem is if you view a helix as the threads on a screw you need to rise roughly 4" for each full circle. As the radius gets smaller the grades increase. some numbers for consideration:
48" radius = 1.3% grade
36"=1.77%
30"=2.12%
24"=2.67%.
The smaller your radius the harder it will be on your engines to pull a train up the grade.
Second factor is the number of loops to reach the new level. 12"-16" is typical dependent on depth of the railroad. So you will need 3-4 loops at 4" rise each to achieve this. Keep in mind that 61’ in HO is an actual scale mile of track. Here is the table for this info:
48" radius = 24’ per loop or 72’ - 96’ of hidden track
36"= 18’ per loop or 54’-72’ per track
30"= 15’ per loop or 45’ to 60’ per track
24" = 12’ per loop pr 36’ to 48’per track.
The questuons that need to be answered are:
- Can I live with the space requirement for one?
- Can I live with my train not being visible for that length of time?
- What else can I do to add a more railroad?
In the last case the current thinking seems to be to build the railroad around the room so the entire railroad rises high enough to form a second level when it reaches the starting point. That way the trains is always in sight and there are no huge space considerations for a helix. After beating this to death in planning for five to ten years I have decided a helix is not the way for me to go and have designed around one level only. Construction starts as soon as the stupid bank dec
here’s another question. Right now I am going to start with a 2x4 module to start (maybe a little longer, I’m not sure). Some time down the road I expand. I envision a upper level over looking the lower level (like a cliff almost). Do I have to use a helix or is there a better way that doesn’t take up a lot of space.
Tom
you will need a helix (at least a semi helix) if you don’t have enough space…a good rule to practice is no more than a 2% grade which is no more than a 1/4" rise every 1 foot…my layout is a 1.5% grade…I rise 1/4" every 16"…Chuck[:D]
Dependent on the type of railroad you intend to model you can achieve the purpose through a series of switchbacks zigzagging up the slope to the upper level. Many logging and mining railroads used this method going up a valley or mountain as far as they could then backing up the next plateau. Built into a model railroad it brings engines to their knees just like the prototype making you make several runs up and down to get all the cars up or down. The old Kalmbach 101 track plans book had at least one railroad using this feature as the center of attention. The steeper the grade the more you will want something like shays or heisler engines designed for this type of service. Even the Pennsylvania had a grade so steep - 5.98% in Madison Indiana they had special SD9 diesels made to handle the grade. Before diesels they used H class 2-8-0’s that were always run facing uphill so the crownsheet would always have water on it and not allow the engine boiler to blow up. On a model railroad you could achieve a level separation of as much as you want in minimal distance based on your grade. First determine the number of casr you can pull up the grade the n make your stub end tracks slightly longer plus any distance between them for thh rise. I would expect you could drag three or four cars up this arrangement to an elevation 24" higher in a relatively small area say 10-12’ long and 24" deep.
One other method you could try is an elevator. Pull you train onto a vertically movable section and raise or lower it to the other level where it can pull onto that section. That way you need one track long enough to handle your entire train and build a sound structure to keep it alligned that moves smoothly and you are in business.
Here is a picture of my helix.
I built this one so I could reach the staging tracks under my main yard.
I used a helix, becuase I had the space to do it and it fits my track plan and operation scheme. and around the walls helix would not have worked for me. I plan to build a second helix on top of the first one to reach the second level. Both are double tracked, with an down and up track. The center is open for maintenance and reaching the trains, in the event of a disaster. I plan to hide the helix with backdrops and mountains. I hope to have the second helix built by the end of the year. I am working on a branch line next to the helix now and then plan to come back and build the second helix.
My friend is designing a railroad with four levels, with a helix in the closet to connect them. Must be several scale miles of track hidden there. In contrast…
I’m designing a plan in a smaller bedroom with no room for a helix of reasonable radius. The track goes around twice (it’s a donut design) to get to a second level which covers two walls (a “deck and a half” layout.) This results in a lot less hidden track, which is principally located on last half of double loop to the upper leve (track closest under the second level.) Perhaps Model Railroader will publi***he plan. I’m sending it to MR tomorrow.
DMNolan, nice work. what type of plywood did you use? I have built several helix’s for friends out of 3/4" Arruco(7 ply plywood) and one out of ABS, I believe the maker was Trainstyles. Any way nice wood working skills.
I usually use 5/8" plywood B/C quality. Nothing special really, I bought it at home depot. I have not had a trouble with sags or bowing.
You could try to build a Nolix, which is a way to climb without a helix. This is a climbing layout that uses several loops at the end of grades, with the loops hidden as tunnels for better realism. This way, your trains stay visible while making the climb up easy grades. Sorry, no pics, but you could do a search for more info.
I’m in school right now so I can’t get the site up, but there was a few of them that I found on the net and would be glad to bring them up when I get home.
P.S. Good luck with the helix, I’ve attempted two of them and neither of them was a sucess. THEY ARE VERY TIME AND MONEY CONSUMING, IF YOU MODEL A MOUTANOUS REGION WRAPP IT AROUND THE WALLS INSTEAD OF USING THEM.
traingeek087,
That would be great if you could post that site. In the meantime I am going to do my own searches
DMNolan, I too like your helix. Very nice job. Have been trying to picture a helix as it would fit in my space. What is the radius of your outside track? Also, how did you cut the plywood? Did you cut the loops as quarter circle or half circle arcs? I could see one joint at the right side of the picture, but not whether there was one 90 degrees around from it. If they are quarter circles, making twelve pieces for what you have, how much 5/8" plywood did you need for them? Lastly, how much rise from one level to the other do you have? I appreciate your reply.
This helix is 10 feet in diameter witha 4 foot rise. The grade is 2%. This is O scale.
wanna build me a helix big_boy_4005?
Charlie,
The tracks on my helix are 38" and 35" radius. The outside edge of the curves is 40.5" and the inside edge is 32.5". The 8" gives plenty of room to space the tracks apart to avoid equipment sideswipes and to put the spacers on the sides of the turns. I use 1x4" cut to about 4" length. With the 5/8" plywood I use, that gives me 4" rise per turn. The helix is 81" across. I don’t know the grade, but don’t have any problem with 2 or 3 locos pulling the 16-20 car trains, up the hill. Here is an under construction shot, with a test train:
I cut divided the turns into 4 sections of 90 degrees each, except the first one. It is about 105 degree cut. That way my joints are not lined up on top of each other. The helix with 11 sections, gives me a 12" separation between the main yard and the RDG staging underneath. You can see it better in this picture:
This week I started building the approach ramp for the second helix that will sit on top of the first. It will take trains from the main yard to the second level. I also am building a branch line that runs in front of the helix. It is about 32’ long and 2’ wide and should have lots of switching possibilities. Its the West End Branch of the Lehigh Valley, in Allentown, PA , for those of you who know the area. I will post photos as they come available (that is once I have something to show.)
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QUOTE: Originally posted by CharlieT
DMNolan, I too like your helix. Very nice job. Have been trying to picture a helix as it would fit in my space. What is the radius of your outside track? Also, how did you cut the plywood? Did you cut the loops as quarter circle or half circle arcs? I could see one joint at the right side of the picture, but not whether there was one 90 degrees around from it. If they are quarter circles, making twel
I forgot to answer this part. I got 6 turns per 4x8 sheet of plywood. So, I used 2 sheets to make the helix.