I run Aristo Fa and B's outdoors. I want to have one train go up and around a mountain. I know that on a straight line your measure by grade about every 100". But how do you apply that on a spiral?
More info: I'm using 5' diamiter track. What I' trying to figure is from ground level, how do I figure how many degrees per inch or foot should the track rise to reach 12" without giving too much of a grade where the train won't be able to climb it) The track will be going over itself in a spiral.
Your help is appreciated.
Jose
By how long the track in the spiral is. I use 3.14 x diameter to get the leinth.
exampel 10ft.dia x 3.14 = 31.4 ft long
Dave
The head is gray, hands don't work , back is weak, legs give out, eyes are gone, money go's and my wife still love's Me.
Remember a grade is "multiplied" by being on a curve. If your goal is no more than 2% on the mainline, keep it to 1% on a helix if you want the same drag. (rough rule of thumb 1.5 to 2 times the drag)
Regards, Greg
Visit my site: http://www.elmassian.com - lots of tips on locos, rolling stock and more.
Click here for Greg's web site
G'day Josev,
Each model engine behaves differently on grades. Some will pull unrealistic loads and others struggle to move their own weight when confronted with a grade. You really need to test your equipment on various grades to see what your locos can do before settling on a standard grade for your mountain run. Set up several lengths of track on a long board and jack it up at one end. Try your loco on that grade and then add cars until you either cannot climb it, or you have reached your preferred train length. As Greg says, the load will be heavier on a curve than on a straight
To measure the grade you will need a builders level about two feet long (or more). Set the level on the track and jack up the lower end until it is level. I do this with packing strips or shims. Now measure the height in millimetres (this will be easier than fractions of an inch when it comes to the math). Measure the length of your level in millimetres. Two feet equals 608mm. Divide the length by the height increase, for example 20mm (just over 3/4' s of an inch). The math here is 608/20=30.4, so the grade is One in 30.4, or as a percentage, 3.298, call it 3.3% (100/30.4=3.298)
I know metric is a little bit alien, but I find it easier than converting fractions of an inch into decimal inches.
Your two foot level should be short enough to use going around your curves, but long enough to stay accurate for the long grades. Now a little trick. If you settle on a grade, say 2.5%, that will be 15mm climb over the 600 mm level. To keep reproducing this measurement, tape a small block, like a lego block, or piece of wood to the underside of one end of your level. When you set it down on a rail top that is at 2.5% the bubble will be centred every time. Just remember to remove the block before you use the level elsewhere.
Good luck and let us know how you get on.
Mick
Chief Operating Officer
Northern Timber Company - Mt Beenak
Since my last post I spotted this video. It appears to use 5 foot diameter curves and rises about a foot. This is roughly what your spiral would look like, in terms of the grade. Also when allowing a one foot clearance you are not just measuring from rail top to rail top. You need to consider the height of your rail, ties and track support (bridge timbers or girders). You would need to allow an extra inch of rise at least to cover this measurement, if you want a foot of 'clearance'.
http://www.youtube.com/user/StefansGartenbahn#p/u/7/j6bCvGWnDZQ
I tried a 9 foot diameter helix, with the minimum clearance from rail head to overhead supports, 10"...
Very tough, only very short trains, short cars could traverse.
http://www.elmassian.com/images/stories/track/helix3.jpg
Mt Beenak I know metric is a little bit alien, but I find it easier than converting fractions of an inch into decimal inches.
I like the metric system for modeling-for me it's more precise.
I know this is off topic, but I grew up learning both Metric and Imperial. I now prefer Metric also. My father was a plumber and had to learn Metric at the end of his working like, and was issued a Metric 'yard stick', a folding wooden ruler that was one metre long and had metric one side and imperial the other. He still uses it in his retirement and every now and again he will give me a measurement as "one metre, 3 and an eighth inches."
Anything smaller than one eighth of an inch was and still is referred to as a 'poofteenth'.
Jose,
I used a cheap picture hanging laser (Stanley Fat Max) mounted on a photo tripod and a yard stick to determine the heigth of multiple points along the helix foundation. My helix is round versus eliptical so a string and a nail provided a constant radius. One foot of rise per 50 feet of run is a 2% grade so the helix needed to be 16 feet in diameter. If you don't have that much room then you will not be able to stack or cross your tracks in a single turn without going steeper than 2%.
You could. try a decreasing radious spiral to go up the mountain... an interesting design problem.
Let us know what you decide to do.
Rex
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