Trying to understand grading

The steep 6% grade will work, however the trains may need to be shorter, or you may need a helper to climb the steeper grade. The other issue with a steep grade is how it will look. You can use some view blocks like trees, buildings and mountains to help make it look OK. I have an 11x22 layout using a 6% grade and a single engine (desiel) can usually pull a 10 to 15 car train. some engines pull more than others. My experience is that Steam engines have less pulling power on these steep grades than diesels.

there are some good threads on making a helix. I do not have one, however I have read about them. The grade would not be as steep as you calculated, because there will be many circles to the helix. The steeper the grade, the fewer circles you need in the helix. The shallower the grade, the more circles you will need for the helix. So you can make a helix for almost any grade you want.

I'm not familiar with the program your using, so no help with that.  On your first helix image you have a 24 inch rise called out.   Simply put, you can pick two of the three variables on a helix, start/end of climb, length of track, and slope. 

An O-72 helix should have a grade of close to 2.5% when each level is separated by 5.5 inches: 226" circumference, divided by 5.5 = 41" run for 1" rise. 41 goes into 100 almost 2.5 times, and that is your grade in percent. Your A-B route appears to have about 1065 linear inches (I see 2.75 full circles and 37 feet of straight track). That yields a grade of under 0.5%. I wish I could tell you what you are doing wrong with the software, but these back of the envelope calculations show that something must be going wrong someplace. Also that you are doing a lot better than you think when it comes to grades, and that at least is good news.

Regarding grades in general, 2-3% is a rule of thumb. Another is that the graduated trestle set many of us had as kids was more like 5%. Really, there is no substitute for testing. If you already have some trains, get them out and play around with them. See what you can get away with in terms of grade, train length, train weight, sharpness of curvature, and the like. Take careful notes so you can refer to them later.

That is a steep grade ! , you also may have a problem with clearance .  Un less you plan on running 5 car trains. under 2% is a better way to go, just because the trestle set is 5%, doesn't make it the correct way!

I am not sure why you chose the parameters you did when creating the helix.  I don't know what software you have. I use AnyRail and creating this helix works a little more straight forward.

I also don't think you'll be able to use 5.5" in a helix because you're not accounting for track, any track bed, etc. I believe that more realistically you need 6.5 to 7" of clearance.

Just because you can design it on a computer, doesn't mean it works in a practical application. , I would try 48" or 60' r,  or just build 2 levels

Grade also is related to the length of the rise.  Often this dimension is in feet.  Your (5.5"), 6", rise over 20 ft, (240"), Run, would be 2.04%.

Rise, divided by Run, time 100%.

Most layouts can do the 5.5".  To do an incline 20 ft. usually requires some extensive work, ??may be around a couple of curves??. Your helix.

I have no idea what you're doing wrong, if anything, with the software you're using, whatever it is?

Anyway, you said the layout is 15x15, but as near as I can tell, the grid appears to 12", so the layout in the photos is actually 15.5x16.  You also didn't say what track you're using, but the numbers in the library along the left suggest GarGraves. I couldn't read the labels, so I recreated it as best I could in SCARM.

It's harder to see the Helix in SCARM, so I offset each level using a short straight track for clarity. As you can see, I get a grade of 2.6% for the Helix with each level separated by approximately 6". Similarly, the main tracks produce a grade of 0.6%. This suggests the software's math is off by a decimal point.

You should be able to go up 7 to 9" using just two sides of a 15' x 15' layout so something doesn't look right.

I can't read the numbers very well but I think you're 6.2% is really .62% slope in your second screen shot.  I think it says that the rise is 6.5 over 1046".

Try using a starting point A of 0, and end point B of 6.5 and see what it says.

I just convert it into 10s. So if you want a 3% grade thats 3/100. So if you want to go up 5.5”. Do 5.5/3=1.83. 1.83*100 = approx 183” of run. Or 15.25 feet.

Gradient percentile:

Rise divided by Length = % of rise.

Example:

4" rise divided by 100" of length = 4%.

Andre

Thanks everyone for the help. It appears I have some more learning with this software (and maybe it has some buggy features). I’ll keep plugging away at it!

You never did say what software you’re using.

@DoubleDAZ posted:

You never did say what software you’re using.

Sorry, it's called Railmodeller Pro. It's on the Mac App Store. SCARM only comes for PC as far as I can tell. And this does a good enough job for what I am looking for right now. https://apps.apple.com/us/app/railmodeller-pro/id952380304

Thanks. I figured it might be that and I don't have a way to test it to see if it's the software or something else giving those weird numbers.

1/4 inch per foot is pretty comfortable. 1/2 inch per foot is pretty tough.

You might try adding 912" or so of straight track, raise one end to 24" and see what RMP says for the grade. I just did that in SCARM and still got 2.6%.