I have two grades in my layout.
One begins at a height of 1" to a height of 4" over a distance of 48 inches.
The second begins at a height of 1" to a height of 4" over a distance of 52 inches.
How would I go about figuring the grade percent(%).
Also, would having curves in the grade make a difference in %.
Thanks
cplmckenzie
Grade % = rise over run times 100. For the first 3(rise)/48(run)x100=6.25%. The second 3/52x100=5.77%. Although curves on on grade can calculated the same way the effective grade is larger due to the friction caused by the curve and requires more power to overcome. There are probably corrections that can be added to figure the compensation caused by the curve. Others may be able to add this.
Joe
the rise divided by the length of the run x100. in your first that would be 3 divided by 48 x 100, giving 6.25 percent…
oops…you beat me to it Joe
No problem Tony. It doesn’t hurt to have someone check my math [:D]
Joe
Hey, Thank for the quick responses (why I am here, just started my railroad Aug. past.
So I’m figuring those are pretty steep grades.
All my loco’s pull 4-5 cars up them, with a good running start.
But I am attempting to do a run with 8 cars plus a caboose and even one of my strong 6 axles can’t seem to do the job.
cplmckenzie
Those are pretty healthy grades. It sounds like you either need to figure a way to lessen your grades or consist a couple of locos to help you up the grade. My choice would be the former.
Joe
There are many archived threads on just this one topic. Many of us compromise a great deal and just accept that we have to have somewhat unrealistically steep grades if our room to get to heights is limited…which it is for the majority of us. Ideally, you should try hard to get your grades below about 3.5%, but even that will make your toy locos work hard to pull more than six to eight cars up them, depending on the loco and the weight and rolling resistance of the cars.
If you are pretty sweet on the track plan and this grade and are stuck on it for now, Joe’s idea may be what you must do: make two locomotives work in concert up grade, just as often happens/happened in the real world.
Thats one way to put it, 6% healthy! [st] I’d think 4% should be the extreme max one would want to go; I’m feeling cheeky at 2.9% but I’m going to be pulling longer grains albiet with MU power.
Do realize that one needs some vertical “transition” at the bottom and top of the grade. If internal to the start of your rise, that will steepen the main part of the grade. If the transitions can be beyond the main grade, that just adds length form start to finish.
I have a modest (most would say small) 5x9 HO layout with a grade to a crossover that is 2.4%. My take on the various advice I had read suggested 3% or less was a typical goal. My first loco was a GP9 that would pull about 2.5 cars per axle max, 10 freight cars uphill without wheel spin. I considered that acceptable. If building again I might seek to attain 2% but would happily do aroud 2-1/2% again. With DCC, I’m finding I prefer to run consists (2-3 locos usually) as I enjoy the ability to do that and like the mixed sounds that slighthly different locos play (e.g., SD50 & SD60). And I don’t run long trains on my smallish layout.
My weakest loco is likely a Bachmann 2-6-0 but I only pull a few cars at a time with it, mostly by preference as opposed to pulling limit.
I’d say the most important part is having a feel for any limitations before finalizing, as I think you mentioned in some testing you’ve done. And tying that with what you might plan to run in the future, or realizing what compromises or changes you might have to make. Another is the realism aspect, as a 6% grade probably looks darn steep; e.g., for a UP mainline vs a logging RR. And paraphrasing one contributor here…it’s your RR so you make the “rules”.
I have 3½% grades on my layout and that’s pushing it to the max. Only my most powerful/heaviest locomotives will negotiate the grade with more than 20 cars in tow. I wouldn’t recommend a grade over 3% for an out of the box locomotive, I have added weight to all of my locomotives to pull the 3½% grade.
Example: My re-motored Rivarossi articulateds have 8 to 10 ounces of added weight, my E7s weigh in at 2½ pounds each. The added weight runs up the drawbar to 4 to 7 ounces.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
My mining branch has woodland scenics 4% grades, two inches rise, a flat switch back and two inches up.
The switch back limits to 3 40’ cars with a proto2000 geep and a caboose.
This is the limit I would go, and note that it is very short cuts of cars. With loaded ore cars coming down.
Dave