# 3% grade ~ Is that too steep? (HO scale)



## scaleddown (Mar 13, 2014)

I am designing a layout on a 5' x 8' table and I find that I am getting stuck with a 3% grade track section. The curve is an 18" radius. The run is about 124" long. Is that too steep?


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## mesenteria (Oct 29, 2015)

How fast is too fast?

Will a ten foot pole be long enough?

Is this music too loud?

All unanswerable questions because information is lacking.

There are 3% grades all over the globe, but they are considered steep. They'll require special motive power or arrangements to add power to what is available. But not necessarily. If it's just the engine going up and down (a hobbyist owns it), then likely it will be fine. If any one engine needs to get 10K tons up that grade, not a hope in hell.

Our toy trains face the very same problems, and for the same reason...traction. Most scale locomotives have plenty of power, even enough to spin their drivers if you hold them in place. What they lack is traction, and that is because they have more power than friction at the rails. They don't weigh enough.

So, the answer to your question is...it depends. What locomotive will you use, and what will trail it in the way of 'tonnage'? Three percent is actually a fairly common grade on our layouts with their limited space because of necessity if we want an overpass. But, it's still steep, and it will probably mean shorter trains. If you are talking three passenger cars that are free rolling (don't have sticky axles), or four or five boxcars, it might be just fine. 

Or not. Mock up what you have in mind, make it pretty sturdy so it is a good representation of what you want to build, and then do trials with all locomotives. You will derive an empirical guideline of what will work.


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

Maybe save that figure 8 overpass for another time when ya have room to spread out.


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## gregc (Apr 25, 2015)

scaleddown said:


> I am designing a layout on a 5' x 8' table and I find that I am getting stuck with a 3% grade track section. The curve is an 18" radius. The run is about 124" long. Is that too steep?


there's also the effective grade of the curve. I think the estimate is 32/rad, so an additional 1.8%, 4.8% total.

it may not be for a train with a small number of cars and/or with a heavy engine.

the pulling power of an engine is probably ~20% of its weight. tuning trucks can reduce the resistance of the cars being pulled.


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## MichaelE (Mar 7, 2018)

Your 3% grade does not take into account curves which increases the effective grade and varies throughout the curve and physical grade if both are not constant.

The effective grade may be 4% or higher using 18" radii.

The ÖBB mountain branch line on my railroad has over 5% effective grade in one area (using 20" radius) but less on the rest. That's pretty steep and the eye is drawn to it immediately, but it is after all, in the mountains and it is not unusual to have that steep grade in the Alps for short stretches of track.


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## Dennis461 (Jan 5, 2018)

" Is it too steep..."
No.


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## mesenteria (Oct 29, 2015)

Not to continue the bad news, but...there's even MORE of it that I didn't get to in my previous post:

You can't make your locomotives and cars climb stairs. They need a grade that's reasonable constant. But they can't get into and out of that slope without vertically oriented curves at the bottom and at the top.

Those curves don't come free; they take up space, and they get it from somewhere between where you need the slope to start at the bottom and where you want it to go back to level running at the top. If you think a bit, you'll realize that it means your constant slope will have to be that much steeper than you had dreaded. What's more, the steeper the grade you need to get your overhead height, the worse the problem gets because your vertical curves will have to be that much longer.

Ok, I'll stop now.


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## gregc (Apr 25, 2015)

mesenteria said:


> But they can't get into and out of that slope without vertically oriented curves at the bottom and at the top.


see discussion of vertical easements and following under Riser Calculations


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## scaleddown (Mar 13, 2014)

Thank you all for the comments. Back to the drawing board. Maybe I will depict crossing the Plains.


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## Atlanta (Apr 29, 2019)

At least it is up to you how steep you will lay your tracks inside helixes or elsewhere.

The prototype RRs tried to lay their tracks as low steep as possible except where the geography disallow steeper grades. 

The physics are the same at the prototypes and in model scales, but in model scals you can use traction tires so that your engines running onto steeper grade more easily than the prototypes.

It giving some general tips for laying tracks onto own layouts...a general meaning is not to use steeper grades of more than 2,5 % if you will have a nice more prototypical model RR.
Steep grades between 2,5 % and 3,9 % are not the ideal possibility but well ok, too.
4 % up to 7 % will be a No Go but gives several prototype RRs using such steep grades, too, like the St. Moritz <--> Tirano RR at Switzerland to Northern Italy or at forrest RRs or any kind of narrow gauge RRs worldwide or tramway or metrolitain RRs anywhere.

The best way of beginning or ending a deep grade will be inside an as wide as possible curve so the breaking point onto top and bottom will be not on straight tracks, there will be the danger of self decoupling during the loco pulls the cars onto top of the RR line.

Onto very steep grades is a common practise that the engine pushes the cars onto top. In cause of self decoupling so the cars cannot run by gravity of itself downhill.

At least it is up to you of what you are deciding.

Me I prefer not to use steeper grades of more than 1,5 % except the modelled prototype used other more steeper grades.


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## MikeL (Mar 21, 2015)

I am very happy with my latest layout iteration - construction, operations, layout, scenery, choice of operating system (DCC), etc. - the only thing I would change is my maximum grade. 

I decided to go with 4% and while I make it work, next time it will be less. My trains struggle to make it up the grade (I need to limit how many cars they will pull) and are jerky coming down.

Mike


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## mesenteria (Oct 29, 2015)

gregc said:


> see discussion of vertical easements and following under Riser Calculations



What is being depicted there is fine IF your locomotive pilots and trip pins don't snag on the rails or the ties with the sharper curves such as the one at the top of the diagram. You can tell that the radius is much less on the top slope, and that would be a distinct problem for, say, my Bachmann Spectrum Heavy Mountain whose pilot just skims above the rails. Again, the advice is always...mock it up and conduct trials; the trains don't lie.


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## Atlanta (Apr 29, 2019)

Hi Mike,

some reality from the practise of steep grades are that the steeper the grade and the tighter the curves it will reducing the cars what will be pulled or pushed in maximum and the more locomotive power you need to climb uphill.

When Germany was an Imperial Kingdom around over 100 years ago it owned some colonies in Africa. 

At the old German South-West African Colony, the today northern Namibia, german military RR engineers had been built a two feet narrow gauge of 600 mm from Swakopmund to Windhuk (Windhoek) through the Khan Mountains alongside in the east of the Swakop Riviere (a river what have water in rain time only) following an old cattle herd trial. 

The normal built up steep grades had in Maximum 3,2 % but between the Khan Station in the bottom and Wellwitch onto top of a Mountain the RR steep grade had been layed with 4,5 % on a Distance of 3 miles around 4,8 Km. The used locos had a power of 45 PS only (PS is less than HP but means the same. The difference came from the past when a british horse needed to pull a wagon onto a distance of one mile and the german horse pulled the car on distance of one Kilometer...around 0,6 Km shorter distance than the british one).
By using two of the 45 PS engines a standard train of 8 to 10 cars loaded with max 8 metric tons the max train speed was by around 10 mph. On there steepest grade of 4,5 % the train needed to be tiled several time by max two cars what needed to push uphill by a max speed of less than 3 mph.
Water was the big problem there inside of the desert. They used lot of water tank tenders. The water cars did not pushed uphill.
The watercars had been filled outside Namib desert.
It took long time until one train had been shunted uphill or downhill. Around 1 1/2 of an hour per uphill or downhill move, five to six moves were needed by each train ride normally.
Standard trains needed a helper engine in the back for faster running.

Around ten years later a private Mining RR built their tracks nearly parallel but used another way than through the Khan Mountains. They layed much better rails for higher speed and for more axle weights with a max steep grade of 1,5 %. A connection to the state RR hab been built later and the state RR never again used their steeper grade lines again and used the private RR tracks, too.

This example is showing you what can happen when steeper grades becoming a big problem by powerless engines.

All we know allready about steep grades had been done in the past by try and error.


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## Gramps (Feb 28, 2016)

This may be way out there but, assuming it's a figure 8, what if you cut out the section of table where the lower level track will be and then construct something helix-like to suspend from the bottom of the table. The train would then go below the table to get underneath the upper level. This should half the distance it takes to get from the table top to get over the lower level. I don't know how to do this but it's something to think about.


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## gregc (Apr 25, 2015)

Gramps said:


> The train would then go below the table to get underneath the upper level. This should half the distance it takes to get from the table top to get over the lower level.


the grade depends on the vertical distance traveled, not the distance above the floor. the horizontal distance is unchanged.

another way of thinking about it is that you go up half the distance but travel horizontally half as well.


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## Gramps (Feb 28, 2016)

gregc said:


> the grade depends on the vertical distance traveled, not the distance above the floor. the horizontal distance is unchanged.
> 
> another way of thinking about it is that you go up half the distance but travel horizontally half as well.


I'm not really understanding the "distance from the floor" response. My thinking was that if the train needs 3" from the table top to go over itself, it could be done by going up 1.5" and also down 1.5". Instead of needing 150" to get up 3" @ 2% it would only need 75" to go up 1.5" and another 75" to go down below the table top 1.5". This may be entirely wrong but it's something that occurred to me. :dunno:


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## gregc (Apr 25, 2015)

Gramps said:


> Instead of needing 150" to get up 3" @ 2% it would only need 75" to go up 1.5" and another 75" to go down below the table top 1.5".


presumably some distance from the overpass and before entering the curve to go around and up over the overpass, there would be a downward grade lowering the track by 1.5".

from that point, just below the overpass, now 1.5" lower than the rest of the layout, the track would curve around for a distance of 75" rising 1.5" (2% grade) even with the rest of the layout, and then have to rise another 1.5" over 75" (2%) to reach the top of the over pass which is 1.5" above the rest of the layout. The track now has to descend 1.5" to reach the normal layout height.

there are now 3 grades


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

I might have missed it, but did you include the thickness of the roadbed under the track? or will this just be track and ties suspended between supports?


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## scaleddown (Mar 13, 2014)

I am learning so much. Thank you all for your comments. Please keep them coming. I hope to start the build in mid- July.


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## 65446 (Sep 22, 2018)

Will try to make it simple: You can build it the way you see fit.
The steeper the grade the bigger the challenge.. Curves add drag to the train. A curved grade adds that much more drag.
If you have a 10 car train which won't make it up the hill, you can 'double the hill' by uncoupling say, last 5 cars and ascend hill. Take those cars to other side of hill, have an engine run-around track, go around those and go get the others..This is/was a real RR ops.
Is your 5x8 free standing or fixed against a wall ? If against wall, unless you have an access hole near middle, having to reach across 5-ish feet to rescue a stalled/derailed/uncoupled train, or work on scenery/structures/wiring will be a really tough thing including breaking things under your arms..
Real trains don't go in a circle. They're basically squiggly lines with turning facilities at either end [turn table, wye, or balloon track]. If you have the space, you might cut the board to make two, 2'.6" x 8's placed end to end [16 feet] and make it what's called a 'point to point' layout with one of the 3 choices at the ends..This in turn causes the need for more proto ops some enjoy more than a circular ['continual' or 'roundy-round'] layout. Call it, thus, a switching layout.
Finally, before building, you might search 'cookie cutter' and 'open grid' bench work instead of having a flat, solid board..Have fun. Don't bite off more than you can chew.... 
M, Los Angeles :smokin:


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## cv_acr (Oct 28, 2011)

Gramps said:


> My thinking was that if the train needs 3" from the table top to go over itself, it could be done by going up 1.5" and also down 1.5". Instead of needing 150" to get up 3" @ 2% it would only need 75" to go up 1.5" and another 75" to go down below the table top 1.5". This may be entirely wrong but it's something that occurred to me. :dunno:



Which is still a run of 150", so no different...


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## Gramps (Feb 28, 2016)

cv_acr said:


> Which is still a run of 150", so no different...


Yes it's 150" total but with the lower level it's only 75" from the table top to the upper track and that should eliminate his 3% grade which was his concern in the OP.


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## gregc (Apr 25, 2015)

but after descending, you now have to ascend 1.5" in 75" to get back up to table top height


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## cv_acr (Oct 28, 2011)

Gramps said:


> Yes it's 150" total but with the lower level it's only 75" from the table top to the upper track and that should eliminate his 3% grade which was his concern in the OP.


That in no way, shape, or form does that.

Either way you have an elevation change of 3" in 150". The grade is the same in both scenarios. (Although it is 2% here not 3%, assuming the grade is constant over the whole distance.)

1.5"/75" = 3"/150"


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## jbertino51 (Sep 20, 2017)

I have 3% grades on my layout on curves and my diesel engines make it up the grade just fine. Of course you can't pull real heavy cars or too many cars but I have had 3 or 4 cars attached to an engine and they make it up the grade. Just so you know my cars weight meet the NMRA standards. Hope this helps.


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## jbertino51 (Sep 20, 2017)

I have 3 % grades on my layout on curves and my diesel engines make the grade. You just won't be able to have long trains or heavy cars. I have run the engine with 3 or 4 cars and it makes it up the grade with no problem. I even have steam engines that make it as well. Just so you know, the wight of my cars all meet NMRA Standards. Hope this helps.


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## G handy (Dec 31, 2018)

Well it took some work but I was able to incorporate a tunnel and a bridge into the Figure 8 with an 18 inch radius using the Bachmann EZ track for most of it. That's because I had the Bachmann EZ track otherwise I would have used all Flex. I have had as many as 14 cars making it around without a problem. One photo early on in the process of building our layout. And unfortunately we ran into an issue if you remember the movie Gremlins the same holds true to your train set don't feed it after midnight and never ever get it wet LOL things happen. Sometime in the middle of the night that 4 by 8 sheet made its way into a room where I had to work bench and it combined with it and things grew and multiplied. Unfortunately I've been so busy doing other things I haven't had much time to play with the trains but summer is almost in full swing and we will be moving some outdoor plants out of the basement opening up some area so I can do some reorganizing and make some space for a little more track only about another 30 feet but don't tell my wife. LOL two turnouts showed up in the mail yesterday getting ready for a small expansion. But back to the Figure 8 or 3 percent grade definitely doable on a Figure 8 but there will be like absolutely no flat section it's almost all grade whether it be up or down. Also on a 4 by 8 I was able to include an outside Loop outside the Figure 8 I think you can see it in the photos. I used a lot of foam board and did a lot of carving shaving even a rasp and sanding getting a smooth grade. I could have done a little bit better but what I have works pretty reliable.


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## Gramps (Feb 28, 2016)

cv_acr said:


> That in no way, shape, or form does that.
> 
> Either way you have an elevation change of 3" in 150". The grade is the same in both scenarios. (Although it is 2% here not 3%, assuming the grade is constant over the whole distance.)
> 
> 1.5"/75" = 3"/150"


His concern was the 3% grade and he can get that to 2% by going below the table top. The elevation change is the same, 3", but the grade is different, 2% as opposed to 3%.


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## gregc (Apr 25, 2015)

Gramps said:


> Exactly. His concern was the 3% grade and he can get that to 2% by going below the table top as you noted in your last sentence.


i suggest you draw a diagram illustrating the grade from the track below the overpassing track to that overpassing track and the total distance between them.


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## Gramps (Feb 28, 2016)

gregc said:


> i suggest you draw a diagram illustrating the grade from the track below the overpassing track to that overpassing track and the total distance between them.


Sorry, I didn't see this when revising my post to better explain.


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## cv_acr (Oct 28, 2011)

Gramps said:


> His concern was the 3% grade and he can get that to 2% by going below the table top. The elevation change is the same, 3", but the grade is different, 2% as opposed to 3%.


Not by virtue of cutting below the table vs building it all up above the surface. Grade is strictly a rise vs. length of run thing. *Something else* in the design also changed to smooth out the grade.

Two rises of 1.5" over 75" is exactly the same as a 3" rise in a single 150" run. But if you have a flat spot in the middle of that somewhere then it's not really a single 150" run...

1.5/75 = 2%
3/150 = 2%


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## Dennis461 (Jan 5, 2018)

I gotta wonder, how many train sets were bought and sold with 3% (approx) grade? Hundreds, thousands, or millions?


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## J.Albert1949 (Feb 3, 2018)

I remember having an "over and under" set like the first image shown above.

But I was only about 9 years old.
That was 60 years ago!


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## Shdwdrgn (Dec 23, 2014)

Yikes, that Bachmann set only has a grade through half of the curves. Wouldn't surprise me if that one exceeded 4%! I notice the inset picture only shows two cars and a caboose, probably all the more that loco can pull up the grade.


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## Sandman824 (Dec 31, 2013)

I have a 5x9 layout with an up and over Double loop with crossover . It has 4 % grade. One locomotive can pull a few cars depending on locomotive. 2 locomotive consist doesn’t really have any issue. Obviously don’t have 100 car trains in my modest space. I also have mostly 18” radius and short peco turnouts. Mostly have GP locomotives but a few 6 axel.


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## scaleddown (Mar 13, 2014)

A little off topic here. I am about to construct my bench-work, but I am curious as to the various heights folks have from the floor to the working table top surface level. What is the measurements of your table from the floor? Thanks, again.


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## MichaelE (Mar 7, 2018)

From the floor to the first level is 48". It just makes things easier and there is less waste of material.

To the second level is 53", and at the top of the third level is 57.5" to the top of the rail head.


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## gregc (Apr 25, 2015)

they(?) say the layout should be at eye level

a basement layout i help with is high enough that you can sit on a chair with wheels and work under it. There are platforms to stand on when operating if there's a lot of reaching. Hadn't seen this before but found it more absorbing to operate and so much more comfortable to work on underneath.


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## MichaelE (Mar 7, 2018)

Yes, I can sit in a chair and work underneath the layout for wiring and such. I have a lab chair for observing and operating but it is rarely at eye level with three levels.


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