Hello All:
I am working on a track plan and I want to include a 2% grade to a height of 4 or 5 inches. My question is how much track space will that take up? I used to know a mathematical formula for figuring this out but I can't remember it. Any help would be greatly appreciated.
Thanks
Mike
A rise of 1 inch over 96 inches (or 8 feet) is 1% grade, thus,
2 inch rise in 8 feet is 2%.
Dont forget to figure in the 2 transitions you'l need each end from level track to the climb aswel.
Let me try again
S = (Rise/Run) X 100
S = Slope/Grade, %
Rise = Elevation change, inches
Run = Length of track, inches
Hence a total elevation rise, height if you will, of 4" at 2% grade requires 200 inches of track, 5" elevation increases the track length to 250 inches.
Bear "It's all about having fun."
Then add in the vertical transition from level to grade, which should have a total length of one (length of longest piece of rolling stock) per percent of gradient, split equally between the grade and the level. Assuming HO scale, with 85' passenger cars (and the occasional 89' hi-cube,) that adds a foot from theoretical point of gradient to actual point where the rails start to rise (or fall) from level - at each end of the grade. Thus, a total 5" rise at 2% requires 274" of distance (22 feet 10 inches,) of which 48" (24" at each end of the grade) will be transition.
Failing to include adequate transitions will lead to false uncoupling, pilots contacting the rails and general operating unhappiness. This is one place where folks using WS pre-cut grade blocks sometimes run into difficulties.
Chuck (modeling Central Japan in September, 1964 - lots of grades and lots of transitions)
Thanks for the help folks. Now I can get back to the old drawing board!
Im having trouble with transitions. I used 1 foot worth of track to form a transition at the bottom. It did ok but not that great. In fact I suspect that the effective transition is only 6 inches and accomodates a 40' boxcar.
Does this mean I have to generate a 2 foot long transition to accomodate heavyweight passenger cars? For example.. If I use a WS 3% grade ramp made of foam it will make a grade of a constant nature for about 12' I think until it gets a rise of 4 inches or roughly.
Does the new transitions of two feet each mean I need to turn that 12' long WS grade into something like 16 feet? Using one 2 foot transition at the bottom and one 2 foot transition at the top?
The reason I ask is because long time ago in another life, you would bend the sub road bed made of cookie cutter wood until you got the track to fit. It forms a sort of a natural transition.
Actually, that 12 foot long 3% grade should become 15 feet long, of which only 9 feet will be "pure" 3% grade. The other 6 feet will be two three foot transitions, one at the bottom, one at the top.
Agreed that the easiest way to form transitions is with cookie-cut plywood, which is one of the several reasons that I prefer to use a plywood subgrade, foam roadbed (fan-fold underlayment, not chunk insulation) and cardstock track template, all laminated together. I am not a big fan of anything I can't get all the way through with a standard length drill bit (for drop wires and turnout operating mechanisms.)
Chuck (modeling Central Japan in September, 1964)
tomikawaTT wrote: Then add in the vertical transition from level to grade
Then add in the vertical transition from level to grade
And then add the transition on both ends as you indicate.
If your transitions are nice and long, the grade in between them will have to be considerably higher than the straight line from bottom layer to top layer, as in without transitions. So, if you only have 10 feet to rise four inches, you figure the grade to be 3.3% (4" divided by 120" comes to 0.033333333333, which reads as 3.3%) If you dutifully add an 18" transition at the top and bottom, you have an average of 1.6%...only...over the total of the two transitions of 36". Without doing the math, my guesstimate is that the grade proper between them will have to be closer to 4.4%, maybe a bit more in order to meet your 4" height requirement within your 10 foot distance that you have alotted.
You have to have the transitions...simple...but if you include them, you'll have to reduce your grade and height, with the associated changes elsewhere along the trackplan if you are stuck with a maximum length of run on your bench.