I need alittle advice. I need to elevate a segment of track 8" in order to cross over another loop. The question for you engineer guys, how many feet of lateral track distance do I need to achieve the 8" elevation gain? I’m trying to keep the grade between 2-3%. I’ve got plenty of room but am not clear how many feet I should estimate/allow. Part of the grade increase (at the beginning) will also be on 20’ diameter curved track (about about six feet). Any help is appreciated. Thanks.
Grade in percent is the number of units of rise in 100 units of distance… real percentage.
1% would be one inch in 100 inches… 8 inches in 800 inches of distance…
go for the worst case first, 3% is 3 inches in 100 inches… you want 8 inches, then you need to multiply 100 inches by 8/3 or 267 inches or about 22.2 feet to just get up…
remember that a grade is “magnified” when on a curve… although 20’ diameter is relatively gently in G scale, but you better take about 30 feet to change heights.
That’s for 3%…
Greg
Try to keep the grade on the curve as shallow as possible. It’s better to have a steeper grade after the curve than an even grade around it and up to the cross-over.
Figuring grade is really quite simple. Grade in percent = RISE / RUN. If you have a 1 inch rise in elevation over a 100 inch run, then 1 / 100 = 0.01 or 1%.
Assuming straight track and you want to achieve an 8" rise in 3% or less you just need to change the “known” values; or 8" / ? = 0.03 or about 266" (a little over 22 feet)
Personally, I’d keep the curve under 2% and boost the strait over 3%, but your still going to need about 25 feet of track to get there.
If you held a 2.5% grade, you’d need to start it 26.7 feet before the 8 inch elevation you need. You will gain 2.5 inches for each 100 inches you travel. So, to gain the 8 inches you would have to travel 320 inches, or 26.666… feet.
don’t forget that you will want a vertical transition at the beginning and ending of the grade also, going from 0% to 3% will not make your trains happy!
The bottom line is that this is going to take a lot more distance than you think!
Greg
Wow! Quick responses! Thanks all of you. As I said I have plenty of room, so allowing for 30’ or more will not be the problem. Your math gives me the formula I didn’t have. Greg, thanks for reminding about the curve and grade. Probably would have only realized that after I tried to get a heavyweight passenger train over the grade. I’ll definitely allow adequate distance for both grade and curve.
All this is a temporary alternative to building a elevated layout that I hope to start this summer. I expect that to take some time and I’ll need to accommodate for grades on that as well. All your comments will go into a notebook. Thanks again.
Hey Rich,
Why only 8"? Most of all my clearances are 11" to make sure that any person who runs on my layout will not have any problems going through tunnels or under bridges. It this clearance from the top of the bottom rail to the bottom of what ever is going over it?
Just something to think about.
Chuck
Speaking of elevations, what kind of tool can I use to lay them out? I’m going to be laying some track and was thinking of just using a 5’ long 2"x2" and a short 1"x3" bolted to the end that I can mark off in 1/2 deg’s. That way I can get transitions in and out of curves as well as starting and ending the rise. I’m wondering if there is a level or something else that I could use short of a surveyors transit.
Mike Brehm said:I've used this Sears laser level for several years:
I'm wondering if there is a level or something else that I could use short of a surveyors transit.
http://www.sears.com/shc/s/p_10153_12605_00948292000P?prdNo=3&blockNo=3&blockType=G3
It displays vertical angles in 0.1 degree increments and is very accurate as proven by taking backshots. Lots of other features, including good old fashioned bubbles, tones for cardinal angles (45 & 90 degrees), a memory for the last 9 measurements, and it can calculate the number of degrees between two angles. The laser dot is bright and fairly tight (<1/4" at ~100’). I use it either on a small tripod or (more commonly) just put it on the track supported by a couple of known thickness (1") hardwood blocks.
Happy RRing,
Jerry
A step-block and a 4 foot level works well too. I don’t recall where I learned about making one, but it is basically a cube of wood with steps cut in it in .5% increments from .5% to 5% based on a 4 foot run.
I use the same type of level as Jerry. Very accurate! Use it to align across the rails, too; including for super elevation.
Now that you mention it Jon I remember seeing something about that in an old building model railroad book. But I also like bright shinny new things too, like a new level.
Thanks for the help.
Mike
Chuck, If I can raise the grade without going over 3% I’ll do it. 8" is the minimum I know I can easily obtain. Now with the formulas the guys have provided here today, I’ll remeasure and see if I can go higher. Thanks.
I likewise have the same sears level… worth the $$. Go for 10" clearance from railhead, then you can run double stack cars, auto carriers, and also 1:20.3 locos…
Have fun!
Greg
Jon Radder said:An old issue of GR had an article about how to make your own grade level. I think it was 1/8" steps? with a 40" run? I remember it was slightly longer then a standard 36" level. But I could be wrong.
A step-block and a 4 foot level works well too. I don't recall where I learned about making one, but it is basically a cube of wood with steps cut in it in .5% increments from .5% to 5% based on a 4 foot run.
I have that same level. It works great, Made setting my grades very easy.
Using a 48" level (a standard size) 1/4" increments are just over one half percent (.25/48=.0052084). Close enough for me 
I have a 2.5" step block cut in .25" increments yielding a gauge that reads .5% to 5% in one-half percent increments. I also have some fixed blocks at 2% (1 inch), 3% (1.5 inch) and 4% (2 inch) in my grading toolbox.
I’d love to have a nice laser level. Mine is a Costo cheepie and is not accurate at all. Unfortunately, spending $50 on tools is not going to happen until I’m back to work full time (if that ever happens). So for now, I’ll continue using my analog method to measure and set grades
Rich I too think you should plan for more than a 8" height. If my Bachmann shay or even my LGB C+S Forney visited your layout they would barely clear that 8". Go for 10" then you won’t get stuck. Track moves, ballast gets underneath and lifts your approaches to the tunnels and you ill find yourself with problems.
A handy tool I use to check my grades which was suggeted by a friend of mine is a grade indicator used in the construction trade. It is a large platic dial with a magnetic base and a red arrow that measures degrees. It was published in the tips and tricks column a few years back in Garden Railways. Most hardware stores carry them for under $8. I used mine on a 2x4 that I would raise or lower from one end when i was going from one spot to another and when the dial read over 3% I knew I needed to extend my run. I also used some of the equations mentioned here and after throwing them around a bit it got easy to figure them out.
Good luck.
Rich,
One way to reduce the amount of grade at the crossover is to put some grade on the track being crossed over. If you could lower the track by an inch or two or three, with corresponding grade going in and out, that will substantially reduce the amount of rise that you will have to accomplish with the track that is doing the crossover. Highway engineers do it all the time, and so, I expect, do railroad engineers (the other kind :lol: ).
Steve Featherkile said:
...............Highway engineers do it all the time, and so, I expect, do railroad engineers (the other kind :lol: ).
That’s the first thing I do on layout plans to keep the grades within “working” tolerances, provided the “theme” allows for it. :lol: