How do I calculate grade? I want to raise one of my lines hight enough to run over the top of another.
Grade = Rise / Run
For example, if you need to raise your line 3 inches and it takes 100 inches to climb that much that would be a 3% grade (3" rise / 100" run).
If you know how high you need to go, you can calculate the run by Run = Rise / Grade.
For example, if you want to rise 4" at a 3% grade, then Run = 4 / 0.03 or 133" or about 13 feet.
According to most posters here, 3% is close the maximum you should attempt; if you can go less than that you should do so. Remember to use easements into your grade just as you would your curves; and not to jump directly into your grade.
I hope that helps.
The basic calculation is rise divided by run, expressed as a percentage. For example, if you need to rise 4 inches in 8 feet (96 inches), your grade would be 4.17%.
BUT - You can’t just rise from a kink at the bottom of the grade to an equal kink at the top. Grades require vertical transition curves roughly the length of your longest car (or locomotive) for each percent of grade. Allowing 12 inches for standard-length passenger cars and Hi-cubes, the example grade (from level at the bottom to level at the top) will be 12 feet long, not 8.
If you don’t have much length for a grade, it might be possible to depress the lower track to reduce the amount of height needed. Also, while I allow 4 inches (actually 100mm) between railheads, a thin crossing (such as a Life-Like truss bridge or a piece of steel stud) might allow a lesser distance. Just make sure (by experimenting) that your tallest rolling stock will actually fit under the bridge.
Chuck (modeling Central Japan in September, 1964 - with LOTS of grades)
Found this on the web and cleaned it up some.
Grades are expressed as a percentage %.
To figure out the grade percentage of a given section of trackage you need to know two things. What is the elevation change of the track between the two given points and what is the distance between the two given points or what is the grade. Once these are known use the formula below to get your answer in the form of a decimal percentage 0.02 = a grade of 2% and 0.026 = a grade of 2.6%. Also if any two are parts of the formula is known you can use them to find the unknown part. Examples below.
Divide the elevation by the distance to get the grade percentage.
elevation divided by the distance = (%) of grade
a elevation of 3" divided by a distance of 112" = 0.026% or a grade of 2.6%
Now if you want to know what the elevation will be for a given grade and distance. Multiply the grade by the distance to get the elevation needed.
(%) of the grade times the distance = the elevation
a grade of 0.026 times a distance of 112 = a elevation of 2.912".
Note; Most RR’s limit the grade on mainline to around 2.5 %
If your elevation change needs to be meet and your want a particular grade, simply divide the elevation by the grade percentage desired to get the distance needed.
elevation divided by the grade percentage desired = the distance needed.
a elevation of 3" divided by a grade of 0.026 = a needed distance of 115" or 9.58 feet of track.
Please remember to leave clearance f
You can place turnouts without problems at a grade. But you run into problems (or you have some experience [:)] ) when you place the turnout at the transition curve at the start / end of the grade!
Wolfgang