Optimal Grades

[el-capitan]

I've never measured my transitions but I would say they are about 12 inches per grade percent. So for a 2% grade I would need a 24" transition at the top and bottom of the hill. For HO you could probably cut this in half. Just a ballpark number though, not exact.

[ABaileyIAm]

Another issue that makes the answer to questions about grade less clear is that a rise of 3" in altitude is not going to occur in a straight line. The incline will have to begin slowly and increase in the middle and then increase at a lower rate at the top. So a vertical climb of 3" over 12 horizontal feet will require a section of track that will average 1%, a section that will average more than 3%, and another section that will average 1% again. I am not a mechanical engineer, but when I started building my first layout over the past few months I found that I could not just draw a straight line and say that, for a 2% grade, I would start "here" and end "here". Imagine a 2% grade downhill meeting a 2% grade uphill. What would you have in the middle? A very sharp V! And at the top of each end there would be a major problem with derailments and uncoupled cars.

[el-capitan]

Is there a technique to build "vertical easements"?  We have to be able to get from slope to flat (and back) without having the cars bottom out at the top, or having the engine dig into the ties at the bottom.

This is my technique: All of my track is on 3/4" plywood. The plywood will only bend so far. This is how I know that the easement is not to abrupt. Of coarse I am in Oscale. So for HO the same might apply to 3/8" or 1/2" plywood.

[BRJN]

Grand Central,

The Atlas Over-And-Under Bridge and Trestle kit will let you climb up about 6"; if it takes 7 pieces of sectional track (63") on the approach, this is about a 10% grade.  (When I was a kid, we tried to make the steepest possible hill and were limited by the ability of sectional track to flex in the middle - the rail connecters bent, too.)  10% is workable for spurs and slow zones but not for high-speed mainlines or long cars.  John Allen was supposed to have a 12% grade on his Gorre & Daphetid, but I do not remember any more than that.

The ends of the steep slope will be a problem that I do not know enough carpentry to solve.  Is there a technique to build "vertical easements"?  We have to be able to get from slope to flat (and back) without having the cars bottom out at the top, or having the engine dig into the ties at the bottom.

[BRJN]

I recommend you build a long mock-up section and try what you want to do, and see if it works out.  Maybe you will come over the hill with flying colors.  Maybe you will look like The Little Engine That Could.  Maybe you stall out part-way up; then you have to use shorter trains, or double them up the hill, or create a helper district.

At Madison Hill (Madison IN), the PRR had to post specially geared locomotives and put special rules in place to deal with a 6% grade, going up from the Ohio River north towards Indianapolis.  You might want to do something similar, IF that kind of train handling (and specially modifying a locomotive or two) is your cup of tea.  If not, and your existing locomotives are demonstrated not up to the task, then you need easier grades.

Do you have (grand)kids?  One way to cope with climbing a short steep hill is a running start!   Getting down may require a complete halt just before the crest, then creep forwards with brakes primed and ready.

[snorengeorge]

Good information. I will be strating a new layout this fall, Finishing the "trainroom" now. I had planned to use 1-1/2 to 2% grades for my "N" scale. My biggest problem is which track to use, flex of course, but which brand. Steel or nickel, brown of black, weathered or not. "O" what fun. Like my canoing buddie say a bad day paddling is better then a good day working and so goes the same for railroading, models that is.

srngeorge

[Anonymous]

I feel 3% is the max. I have sufficient roster to handle any grade and will break out the BLI ABBA F unit for the worst grades. 3% should work out to about 3 inches climb in about 12 feet of forward travel. 2% is the same climb in about 16 feet which is way easier on the engines.

3" rise over 12' is 2% and 3" rise over 16' is 1.5%.

Thanks much for correction, hard for me to think grade % in inches when I see feet over miles.

[Grand Central]

I think this also is a matter of what you are going for, if you are going for looks, then I think 4% would be the maximun to still "look right" although a little steep. For operation, I would not go above 2%. However, I have heard (but not seen) short sections of 8% being used to get from one level to the other, not sure how or if, that could work. It also matter if you will be using DCC or Analog, since engine control differs between them.

[el-capitan]

I feel 3% is the max. I have sufficient roster to handle any grade and will break out the BLI ABBA F unit for the worst grades. 3% should work out to about 3 inches climb in about 12 feet of forward travel. 2% is the same climb in about 16 feet which is way easier on the engines.

3" rise over 12' is 2% and 3" rise over 16' is 1.5%.

[Anonymous]

Actually the B&O had the steepest grades on the east. All the railroads that arrived after the B&O tried to moderate thier grades.

I feel 3% is the max. I have sufficient roster to handle any grade and will break out the BLI ABBA F unit for the worst grades. 3% should work out to about 3 inches climb in about 12 feet of forward travel. 2% is the same climb in about 16 feet which is way easier on the engines.

My preferred performance standard on a 3% is the ability to stop, hold the train on the grade and then restart with minimal slipping for steam engines by themselves. Anything more, the train gets a helper.

I did assemble a train that turned into about 50 feet of frankentrain with metal couplers, plastic horn hooks, plastic wheels, metal wheels train set, blue box or all of the combined. The slack when it ran out on starting reached over a foot in length. whew.

My longest regular train as of right now is about 15' plus 2 feet for the engine. That is about 12 heavyweights, three express cars and the PRR Duplex or roughly 26 freight cars and caboose. I dont have any grades as of right now so I cannot tell you how it runs as a complete unit. Ask me again in a few months after I have tested the entire train on a grade locally.

[nobullchitbids]

I seem to recall that the limiting grade on the (real) B&O was 2 per cent.  I believe this was pretty universal in the Northeast.

With the exception of the top of Cajon Pass, the limiting grades on the U.P. are the 2.2 per cent in the Blue Mountains.  Real railroads don't like to go much higher than that.

You definitely want to pay attention to the recommendation to use steel rail rather than nickel silver on hills -- NS will polish over time, and your engines will slip.

[el-capitan]

I've got 3.5% grades. I hate them and on my next layout 2% will be the max. They look too steep (IMO) even though the atsf had them on Raton. And I am limited to the amount of cars one engine will pull up the grade. I really don't want to use helpers.

If I could I would make the whole layout one level with no grades.

If you use steel rail on steep grades you get better traction. I would say 25%.

[loathar]

4% a little steep. I've got about 2.25% with 26"-30" curves and an Athearn GP 38 can pull about 12 cars. My cars all roll pretty good. About 1/2 have metal wheels. If I add a second loco I about double that to around 24 cars. As mentioned there are a lot of variables. Tighter curves will cause more drag. And remember, what goes up slow will come down a lot faster.

[dehusman]

Depends on what engines. 

Get a 8 ft 1x4 and 4 or 5 sections of flex track.  Attach the flex track to the 1x4 and let it trail off the bootom end.  Raise the other end 1" for every percent of grade you want.  then put a test train on the tracks and see if it will pull.  If it won't pull up the stratight, then it won't pull on curves etc.  Get 1/8 in material (particle board, balsa wood, etc).  Make a stair step out of layers of the 1/8" material.  Build it up until its about 3/4 to 1 in thick.  If you use a 2 ft level each step will represent about 1/2% of grade.  Quick and dirty way to set grades.

Dave H.

[CP5415]

I have 2 3.5% grades on my layout. Both of these grades have curves in them.

A single stock Athearn BB SD40-2  has had no problem hauling 30 freight cars up these grades.

I wouldn't go any steeper than this if you can help it.

I plan on having shallower grades next time out.

Gordon

[selector]

...on the grounds that a train that will pull a 2.5% grade isn't likely to have problems with 2%...

Can't beat that logic. 

[tomikawaTT]

I attacked the grade question from the opposite end - what did my prototype do?

The local megarailroad had a 2.5% grade (25/1000 in metric equivalent) between the two stations represented on my layout.  Therefore, I have a compensated 2.5% grade between those points.

The local feeders ran upgrade with (mostly) empties, and downgrade with loads, on 4% grades.  I've discovered that I can easily duplicate that.

On hidden track, I limit my grades to 2%, on the grounds that a train that will pull a 2.5% grade isn't likely to have problems with 2%.

Just my .  Feel free to disagree.

Chuck (modeling Central Japan in September, 1964)

[selector]

Your question of an optimal grade cannot be practically answered.  The reason is that there are so many variables ranging from your skill in laying track to a properly eased grade, a consitent grade, the type of locomotive, the type of car, the length of train, curves and their radii, the condition of the axle retainers in the trucks, and so on. 

Pick a train that seems reasonable and you may find that it can take grades all the way up to 6%.   But what train would that be?  Probably a hefty locomotive and no more than two heavyweight passenger cars....although I doubt even that would work.  Is that optimal?  If that describes your needs, then you betcha.  If you shake your head and tell me you have visions of four SD-45's and 20 autoracks, it is very possible that your optimal grade, if by that you mean the steepest passable, is still going to be that nasty 6%...although I doubt it.

I see you have resorted to trying grades first.   That is always the best and surest way to find your limitations.  Then, you have to match the grade and other conditions when you actually place it on the layout. 

Good luck.

[twhite]

I find that it really depends on the locomotive.  My layout has 34" minimum radius curves and my grades are mostly 2-2.2% with a very short section of 2.4%.  I don't run diesel--except for a few passenger trains--so I can't really comment on current diesels and their pulling power.  However, with the steamers I run, I find that if I'm going to go above 18 or 20 cars for train length, I'll either have to doublehead non-articulateds, or use my heaviest articulateds.  Luckily, my curves are wide enough that I don't have to worry about pulling cars over on the grades, but I still have to plan motive power quite carefully when I'm making up a train.  But then, that's half the fun of operating, IMO. 

4% is a pretty hefty grade in anyone's book, unless you're modeling a short-line or a logging railroad.  I can only think of two instances on prototype mainline railroading where that type of grade comes into play, on the ex-Santa Fe mainline for a short stretch over Raton Pass, and the now dormant Saluda grade on the ex Southern Railway in South Carolina.  Both Rio Grande and Southern Pacific had 3+% grades on Tennessee Pass and Siskiyou Summit, respectively, but Tennessee Pass is shut down (temporarily, let's hope) and the SP Siskiyou Line was sold to a short-line railroad that operates only about one train per direction per day. 

Mind you, I'm not playing Rivet Counter and trying to dissuade you from a 4% grade on your model railroad, because I know a lot of modelers use it (I did too, on my first layout).  But depending on BOTH the grade and the radius you choose, you'll have to be careful about both the length of your trains and the power capabilities of your locos.   Multiple unit lash-ups will probably be your best bet.   

Tom

[Anonymous]

I am adding a 4% grade to my layout too, and I pondered the same question. My friend Nathan uses a 4% grade on his layout too, and I had experience operating on it. His Athearn GP38-2 can pull around 10 cars max., so it really depends on what engines you are using.

I don't know about other engines, but on my layout my trains will be about the same leingth, and I will use 2 or 3 2nd generation deisels (my railroad is set in the present and uses mostly second hand engines) on most trains depending on leingth. Really heavy ones may require helpers.

I normally decide on what looks right, not on what they can pull. Most trains have twice as many engines than they would need in real life. They look SO much cooler with 4 engines![:D]

Hope this helps,

---

Tyler

Springfield Central Railroad

Route of Pittsfield Pass

 

[Anonymous]

Dan and Robert, Thanks for the reply. I opted for 3% grade mostly on the straightaways and some on 28" radius curve. Tested a few of my engines and they seem to do fine.

[Anonymous]

There are several factors to consider in giving you a reliable answer. The heavier your power units the better they'll do on any grades.
For Example I find a 4-4-0 will pull about 5 cars
up a 4% grade. Twice that if it has traction tires. Narrow gauge eguiptment being lighter do
worst and diesels do better. If you are planing a layout for geared engines, they like the prototype will have less problem with these heavy grades. On one of my layouts I was pulling 5 loaded log cars up an 8% grade with a PFM Benton
Shay.
I hope this helps.

[Anonymous]

The steepness of the grade will determine a lot of things about your layout. The amount of curve on the grade is another controlling factor to think about. Curves add to the resistance of the train as well as the rise of the grade. You said that you don't have a lot of space so I would guess your minimum radius is near 22". This can cause long cars that are top heavy -auto racks for instance-to tip over. Even the "regular" rollong stock needs to be properly weighted and free rollong.
You need good electrical connections too. Jerky operation causes the cars to pull over. Starting a train on a curve and grade will do the same unless you have good speed control.
I run 40 to 45 car freights with 3 or 4 powered engines up 3.5 percent grades and 30" rdaius curves all the time. One of these is a complete loop where a very long train can pass over itself twice. The only time I pulled the cars over was when I was going for "the record". I tried a 100 car train...bad results! 75 has been the max so far.
I model the west so the grade of 3.5 is what the ATSF has over Raton Pass. There are some steep grades in the east too just not a many I would think. Southern RR now NS has a 4% grade still in use.
Good luck. Good track work and good electrical work is important.

[Anonymous]

I am starting to build my first layout with grades. Prefer northeast look and feel. Don't have a huge space to work with yet want to work in some bridges. Mostly run trains with 10-20 cars. Is a 4% grade too aggressive for most engines? if so what is best?