What is the most accurate way to figure distance for a 2% grade in N Scale. I have torn down my old layout and drawing up a new plan and want to be more accurate with grade for the new plan. DR
hi,
you have to compensate for curves and vertical easements.
1) for vertical easements it depends on the length of your cars and the steepness of the grade. Add the length of your longest car or engine for every 2% change of grade; both at the top and bottom of the grade. If your longest car is 72 ft long in prototype, the length in N will be about 4,5". For a 3% grade you should add 4,5 x 3 / 2 = 6,75" at both ends of the grade; in total 13,5 inches.
2)In HO the compensation for curves is 30 / R; it could be about 16 / R in N-scale. When apply-ing a 12" radius the compensation will be 16 / 12 = 1,25%. This is a lot; to keep the grade comparable with a 2% grade on a piece of straight track, your grade can't even be 1%. (2 - 1,25 = 0,75)
If the difference in heigth is 3 inches and the grade is 2%, you could calculate like: (100 / 2) x 3 = 150 inches is the length you'll need. Add 13,5 inches for vertical easements and the total length will be 163,5 inches; almost 14 feet. But compensated for curves as well: length = (100 / 0,75) x 3 + 13,5 =413,5 inches, almost 35 feet.
Depending of the lenth of your train most engines can handle a 3% grade. However tight radii on small layouts is limiting the use of grades severely due to the compensation for curves.
BTW the rules of thumb above are only an indication. You could setup your combination of curve and grade and try out how your trains will behave. Also the length of the grade is important, do not make it to short.
Smilepaul
Thanks for the great reply.Fantastic datas,I loved every bit of it.Unfortunately,most modelers have to cheat or we couldn't have a layout but still,it gives a very good idea of how and where deviations from the ideal can be designed in a layout plan so that somewhat prototypical operations can be achieved.Still too steep...well...just add locos.Great infos,thanks again.
Thanks Paul, I'll work with this info and see how to make my new on going design work. My smallest
"R" is 18" and the rest in the low to mid 20's for the new plan I'm working on. Thanks, Doug
rgengineoiler What is the most accurate way to figure distance for a 2% grade in N Scale. I have torn down my old layout and drawing up a new plan and want to be more accurate with grade for the new plan. DR
I hope you understand that the run over rise computation for grades is irrespective of scale. A rise of one inch over 100 inches is a grade of 1% in any scale, right from the real world down to Z and anything smaller still visible to the naked eye. And beyond.
From the above, if you want a 2% grade, you would need each inch in height to be gained in only 50 inches, not the full 100 inches. So, if you want 2 inches in height, you would want 2 X 50 inches of travel, or 100 inches. Our reverse check shows us rising 2 inches in 100 inches, or the 2% grade we desired.
Thanks for reply. I am aware now that scale means nothing. The answer of 1" of rise per 100"'s confirms what I thought for 2% grade but wanted to be sure for my plan drawing. Thanks Doug
rgengineoiler Thanks for reply. I am aware now that scale means nothing. The answer of 1" of rise per 100"'s confirms what I thought for 2% grade but wanted to be sure for my plan drawing. Thanks Doug
Maybe you just have a typo mistake from the understanding of the explaination of grade previously. 1"in100"= 1%, 2"in100"=2%
If you want to make a simple tool to set that 2% grade, tape a 1/4" block to the end of a 2ft level. The 1/4" is close enough in 2 feet for the proper grade. If you do the math it is more like 9/32nds.
1/8" block will be 1%
1/4" block will be 2%
3/8" block will be 3%
Modeling B&O- Chessie Bob K. www.ssmrc.org
I know you are in the planning stage and drwaing your layout wiht the ideal grades.
The 1 inch rise over 100 inches{1% grade} or 2 inch rise over 100 inches {2% grade} is the simplest grade explaination. It is less complicated that way. I was wondering why no mentioned thatm until Selector did.
It should also be mentioned that Of course if you have curves in the rise, then you effectively increase the grade as it adds stress to the loco{s} pulling hte train.
I just wanted to point out the Woodland Scenics make inclines and risers to make great grades in flexible sturdy foam. They are premade to 1% , 2% grades and up. The incline provide the rising ramp, and the risers are like flat level "pillars" on top of which go the next incline, or the level upper height of trackbed..
They are availble here:
http://www.wholesaletrains.com/HOProducts2.asp?Scale=None&Item=WDSSUB
I found them VERy easy to use and guaranteed perhaps a better job of the incline {ramp} than I could do. They may be a bit expensive if you are doing a large area, but well worth looking into.
I DID learn the hard though, that 3% and 4% grades ARE NOT DESIREABLE. 2% is my MAX now.
That's my story and I'm stickin' to it.
Just my
-G .
Just my thoughts, ideas, opinions and experiences. Others may vary.
HO and N Scale.
After long and careful thought, they have convinced me. I have come to the conclusion that they are right. The aliens did it.
A Typo is correct. I have torn down the layout that I built 23 years ago and could not remember how I had figured the grades back then which were, in some spots, steeper than I would like for pulling long trains. I want the new layout to be no more than 2% if I can do that in my space. I also am aware of curves and the pulling stresses they create. Also I remember that I had set up a level to figure grades and you have sparked my memory now with wood blocks on a two foot level. My layout was closed up for about 18 years. There have been many changes since then and now I have time to work on a layout and start over for the better. Thanks for all the comments. Doug R.