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
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
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
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.
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)
tomikawaTT wrote: ...on the grounds that a train that will pull a 2.5% grade isn't likely to have problems with 2%...
...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.
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
Brought to you by the letters C.P.R. as well as D&H!
K1a - all the way
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.
Dave H. Painted side goes up. My website : wnbranch.com
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%.
Check out the Deming Sub by clicking on the pics:
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.
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.
Safety Valve wrote: 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%.
el-capitan wrote: Safety Valve wrote: 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.
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
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.
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 wrote: 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.
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.