O-Scale Helix

Alan BrandoliniOGR Forum Member

I am planning an O-scale Helix employing Gargraves 54" curved track. I will be climbing 32" to run a train around my ceiling. I found a Helix Design Calculator from modelbuildings.org which calculated with a 27" radius the ring diameter will be 58"; the vertical distance between rings is 6"; ring circumference is 182.12 "; the grade is 3.29%; rings needed is 5.33; length of each segment is 91.06". Assuming the above calculations are correct, I do not have room for anything larger than a 54" diameter. My questions are many; Does anyone manufacture an O-scale helix? What material should be used? are the calculations above correct? has anyone published an article on an O-scale helix? with a 3.29% grade, will engines be able to travel both up and down? As you can see I am looking for any and all assistance. Thanks!

7/12/1811:15 PM

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MELGAROGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

I verified all the numerical values that you quoted, although the circumference (at the ring radius of 58") is 182.21". With a rise of 6" and a run of 182.21" the tangent of the elevation angle (at the ring radius) is 6/182.21 = 0.0329 = 3.29% grade and the elevation angle itself is 1.886 degrees. The calculator has added 4 inches to the nominal 54-inch center-rail diameter of O-54 track to get the ring diameter of 58 inches. This is equivalent to a center-rail radius of 27 inches which, plus 2 inches, gives a 29-inch ring radius (58-inch ring diameter). So, the calculated values are correct. If your ring diameter has to be reduced to 54 inches, the grade is increased to 3.54% and the elevation angle becomes 2.026 degrees. First of all, what are the center-rail radius and outer diameter of Gargraves O-54 track? If you want to know the center-rail radius/diameter, measure the distance (along a straight line) between the ends of the center rail of a curved piece of track and I will calculate the radius/diameter for you. Better yet, just lay down a circle of Gargraves O-54 and measure the actual diameter. I believe these grades are acceptable on straight track (with traction tires?) but you will have reduced load capacity on the O-54 helix.

MELGAR

7/13/181:11 AM

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JanOGR Forum Member DIGITAL SUBSCRIBER

The 58" outside diameter provides for a 1.5" clearance outside the outer rail. All the rules for overhangs apply. Also, your track is 0.5" high which reduces the separation from 6" to 5.5". If you use 1/2" plywood, your clearance for trains drops to 5".

Jan

7/13/187:21 PM

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ogaugenutOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

I want to make a minor observation that may help with design. A helix does not have to be a circle. Here is one I made decades ago with O42 curves and probably about 3' straight sections. I would do differently if built again. Not sure of the grade.

Bill

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7/13/189:35 PM

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mike g.OGR Forum Member DIGITAL SUBSCRIBER

Very cool looking Bill! thumb

7/14/1810:15 AM

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boomer0622OGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Alan, here are a couple pictures of my double helix, I used 7/16' threaded rod as my vertical supports with nuts and washers. I didn't use a lot of mathematical formulas just common sense and trial & error. The one on the left is 0-54 Lionel tube rail. If I can help out with any construction questions my email address is in my profile.

Doug