This is my first go-round at a layout with grades. I am going to be doing N-Gauge and was wondering if I should go with a 1% or 2% Grade , and wether or not I sould do this on a curve, straight section or combination?
Thx in advance for any help.
malcolm
You shouldn’t have a problem with 2% grades. 2% grades are very common. Typical model railroad length trains are very short by prototype standards but still use full sized diesel locomotive consists.
Curves do create additional friction on the wheels and thus increase the locomotive power required to move a train just like a steeper grade. Thus it is desireable if possible to lessen the grade on a curve. However, for the vast majority of model railroads, this doesn’t really matter and has little noticeable effect as modelers tend to have ample locomotive power for the trains they typically pull.
The only time you may have to be careful with grades is with steam locomotives and long trains. I would like to run ~40 car trains pulled with one HO scale Berkshire steam locomotive per prototype practice. I have to minimize grades or I may not be able to pull my desired ~40 car train with my Proto2K Berkshires. I know a 2% grade will be too much here. I know I’ll have to make sure all my cars roll well (metal wheelsets) and I may need to try to add weight to my locos for extra traction.
To add to Eric’s reply, You should indeed by okay at or below 2%, but it really depends on what you want to climb the grade. If you don’t mind doubleheading, then maybe even 4% would be okay, but you may have to cut your train down to 15 cars or less.
Eric was quite correct to point out that curves add to the demands placed on the locomotive. If your curves will be in the medium to broad range for your scale, you will likely have little effect on your loco with a moderate length of cars. Drop down to 7 or 8", though, and you may be in trouble. (I am in HO, and am not conversant with the typical radii, so forgive me if my figures above are actually considered moderate).
My message to you, though is this: if you are going to have a loop such that part of the track passes over itself at some point, make sure whatever grade you choose has enough distance to clear the lower track with enough room for the supporting structure below it. That length does not include easements into and out of the vertical curve at each end of the grade.
Selector,
7 or 8 inches would be very tight in N. Thats more in the area of Z scale, or maybe a tight Nn3 setup. 9 3/4 is generally concidered a tight curve in N and something like a 15 inch or so being concidered moderate by most standards. Personally I go for larger, but even a 19 inch curve is concidered quite broad by most.
mwyllie,
The comments made so far are right on the money. The trick is matching a broad curve with a low percentage grade. As you raise the grade or tighten the curve it affects the train. A small test setup will determine what works for your application.
I’d set up a piece of plywood and figure the grades for different heights. Then just get some double sided sticky tape and lay some sectional track on it, hook a power pack to it and try it, with loco’s and cars. Use sectional track so you know the radius is right. Try out a few different radii and change the grade till you find what works best. It’s a small investment that will save a lot of headaches later.
Also, remember that you can sometimes use a bit tighter curve and not adversly affect the train if you use easements. For example, use some 15 inch easements on an 11 inch curve. You make the center of the curve 11 inches, but the ends are 15’s. The train will track through the corner better and drag will be reduced.
On my old HO scale layout I had a grade that continued on a curve - big mistake! Even though I had the motive power to make it, the total weight of a long train, especially with cars stil on the lower end of the grade, would sometimes force the cars just behind the locos to tip over! Argh… I also had very tight curves (18" radius) and even ran Superliners and Auto Carriers…Needless to say that is the main reason why I decided to give up HO and go to N scale!
So if I were you, I would try as much as possible to make the incline on the straightaways, and if it reaches a curve, level it off.
I’m in HO and I have 3 grades on my layout, 1 on a straight-a-way and 2 on 22 inch radiius curves with no easements. I’m guessing that would be around 11 or 12 inch r. in N? I typically run trains that are no more than 12 cars long, all with metal wheels. The straight grade is, of course, the easiest to negotiate and it is probably about 2 percent. One of the curved grades is a hair over 2 and one is a flat out 3 percent. While I don’t have any problems with them if I had it to do over I’d try and make that last one a little less. Another problem to keep in mind with high grades is the transitioning from the grade back to level, especially if you run long cars such as passengers, because of the uncoupling factor. If you can, try and make that transition as long as possible to keep the aggravation level down.
JaRRell
On my last HO scale layout, I had a 3% grade on one side and a 2% on the other. I know that’s a bit steep, but for the trains I ran it was OK. I did use 4’ long vertical easements to transition from level to 3%, the easement was basically the track board flexed from level to 3% grade. I attached one end of the board at level, the middle at the proper 3% elevation, as well as the other end. My grade was calculated to end 24" from the end of the board, but instead I let 48" of the board gently curve to provide a very gentle transition. I also used the same technique for the transitions to grades. I plan on using the same technique on my next layout that has grades.
Brad