# Rules for inclines



## Mattsn (Nov 22, 2015)

Guys, as I'm figuring out my track plans I realize I want to build an incline that would allow one train to pass over another. However I dont know the rule, assuming there is one. Meaning is there a rule of how many inches of incline per foot of travel? And would thay rule also apply for descent ? 

I suppose the length and weight of a train would affect this and this would not be for a long or heavy train. 

Thanks


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## dave1905 (Jul 7, 2013)

Grades in US are expressed in %, that is the rise divided by the run. A rise of 2 inches in a run of 100 inches would be 2/100 =2%. A handy rule of thumb is how many inches of rise in 8 ft (96 in). So a 2 in rise in 8 ft is about 2%.

Conventional wisdom is 2% is a "normal" max for trains and 4% is a max for switching moves or very short trains. The steeper the grade the more you have to worry about transition curves at the top and bottom of the grade. If those aren't long enough the cars will uncouple and engines may bottom out or have pilots hit the rails.


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## D&J Railroad (Oct 4, 2013)

Depending on the size of your operating area, grade may or may not be a factor in what you want to do.
Typically, a 2.5% grade is about the most you would want to build. You can determine that by first, determining what the summit height is. In your case, to pass one track over another, you will need about a 3.5" rise, and that is just the clearance for the train. Factor in your roadbed material and you have your total climb. Now, to determine the actual grade, just do a little math to determine what 3.5" is 2.5% of. 
H = 3.5"
G = 2.5%
L = length of track.
H ÷ G = L = 140"
You will have to factor in a little bit of easement where the level track changes to an incline. That might add about 10" to the top and bottom of the grade.
For a smaller layout area, you probably exceed that grade because your trains won't be that long.


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## CTValleyRR (Jul 26, 2014)

The "required" clearance (top of rails to bottom of overhead obstruction) varies depending on what era you model. NMRA Standard S-7 discusses clearances, but the largest one (modern equipment) is 3-5/32", so 3-1/2" is ample.

Generally, using "reasonable" grades precludes using them on a 4x8 layout, unless pretty much your whole layout is devoted to grades (at 2%, you need 175 linear inches to achieve that 3-1/2" vertical separation, and another 175 on the way back down, not counting easements, for 350") A hypothetical track around the perimeter of a 4x8 is about 225", give or take). Even the 2.5% Ken calculated above needs 280", not counting easements.

Having a curve on your grade further reduces the ability of a loco to pull a train up it, so that's something else to keep in mind.


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## Mattsn (Nov 22, 2015)

My layout is basically a "U" shape, 12 feet long with 8 foot sides.

Thanks for the info


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## bluenavigator (Aug 30, 2015)

There is a way to shorten the length of the tracks if the track is going over other track is to have the lower track to go down while upper track is going up.


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## D&J Railroad (Oct 4, 2013)

bluenavigator said:


> There is a way to shorten the length of the tracks if the track is going over other track is to have the lower track to go down while upper track is going up.


That's kinda what you're doing anyway when you are limited on how much track have to work with.


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## mesenteria (Oct 29, 2015)

Don't take any shortcuts here: what do you want to run on your track system? What's the height of the highest point on your rolling stock? For example, do you have a caboose with an extra high chimney for its stove? I do. How about a wrecking crane...those booms can get pretty high, or their cable supports. Do you have a pantograph on an electric traction motor? My Trixx GG1's pantograph told me I HAD TO have a minimum overhead clearance of 3.9". With the length/run I had to play with to get my self-imposed minimum of 4 1/8" overhead, including 12" vertical curves at the top and bottom of the grade, I have to have a grade of 2.4%-ish (the actual construction always changes things a bit).

Suppose you find that you can comfortably fit a grade, with the appropriate overhead clearance, of about 3.1%. What can your locomotives tow up that grade? Do you have a small passenger train that will be no problem, or a string of 14 heavyweights from the WW II era behind a Pacific or a couple of GP 9s? 

This is what I meant by my first comment. You must set some strict, DO NOT FUDGE! criteria that you know you must adhere to strictly. From there, do some hard and cruel math. Will it work the way you want to play? If not, you have options, including rethinking your track plan before you spend time and money on one that leaves you really disappointed in both it and yourself.


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## bluenavigator (Aug 30, 2015)

Glad that I have no plan to have crane or caboose. Mine would be modern era, which are often being "cabooseless." 

On the side comment, I am not going to buy that longest rolling stock, which I just forgot what it was called...oh, yes! Schnabel car!


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## Mattsn (Nov 22, 2015)

I watched a few you tube videos of HO scale locomotives pulling up 3 and 3.5% grades. None them trailed dozens of cars but varied between 6 to maybe 12. My idea would be a steamer pulling just a few coal cars. Nothing heavy. Ill have to do some research and maybe build a test track.


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## MtRR75 (Nov 27, 2013)

Mattsn said:


> Ill have to do some research and maybe build a test track.


If you have some track and any kind of a table (like a kitchen table or a shop table), you can easily test different grades.

Make sure that the table is level. Lay some straight track on the table -- lengthwise. Just tape the ends of the ties to the table to keep it from moving. Hook up your transformer and set your train on the track.

To test the inclines simply put shims under one end of the table to raise it. Use the thickness of the shims and the length of the table (leg to leg -- not the surface) to calculate the incline percentage.

This simple system does not factor in curves, which add more resistance. But it's a start. You could put curved track on the table, but the grade calculations becomes tricky -- it is no longer the same as the table grade. Also, the actual grade of curved track on a flat table changes as you go around the curves.


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## Mattsn (Nov 22, 2015)

MtRR75 said:


> If you have some track and any kind of a table (like a kitchen table or a shop table), you can easily test different grades.
> 
> Make sure that the table is level. Lay some straight track on the table -- lengthwise. Just tape the ends of the ties to the table to keep it from moving. Hook up your transformer and set your train on the track.
> 
> ...


I was thinking if the same thing, except I was gonna use an 8ft 2x4


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## MtRR75 (Nov 27, 2013)

Mattsn said:


> I was thinking if the same thing, except I was gonna use an 8ft 2x4


That works, too -- as long as the 2x4 is perfectly straight.


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## CTValleyRR (Jul 26, 2014)

Mattsn said:


> I watched a few you tube videos of HO scale locomotives pulling up 3 and 3.5% grades. None them trailed dozens of cars but varied between 6 to maybe 12. My idea would be a steamer pulling just a few coal cars. Nothing heavy. Ill have to do some research and maybe build a test track.


I have a Proto 2K Alco PA that can pull 4 passenger coaches up a 6% grade (maybe steeper -- that's all I've tested). The issue isn't just pulling power, but the ability to transition TO the grade and off of it again. Even though my loco can handle the grade, it would need serious easements to avoid derailing or uncoupling at the top and bottom. It's hard to predict how any loco or car will behave unless you actually test it.


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