I am looking at making a incline but am trying to remember the formula. is it 2" drop for every 8' of length or 2" drop for every 100" ? where would I find it?
Figuring the grade percentage is a rise to run calculation:
Grade (%) = (Rise/Run) x 100
Rise and run can be in inches, millimeters, miles, or kilometers. But they have to be the same unit of measure.
If you prefer a 'fill in the blanks' solution, you'll find it here: http://railroadboy.com/grade/
Len
There is a simple way to set up an incline in real life. Since grade percent is usually calculated on a model railroad as inches of rise over a 100" section, you can reduce the amount of those dimensions.
Thus, each percent of grade would equal 1/4" of rise over a 25" run, a much more manageable distance. If you are building a layout from the ground up, you probably have a 24" carpenter's level. When building your incline, you can measure its steepness by slipping 1/4" pieces of moulding strip under the downhill end until the bead sits level.
2" per 100" is a 2% grade. Since there is only 4" difference between 8' and 100" it is real close to 2%. 2" per 8' (96") would be 2.08% grade, 3" = 3.125%, 4" = 4.1666%.
thanks, terry toenges, jward and len.
The simple thing, which is close enough for model RR work, is this: 1" in 24" = 4%; 1" in 36" = 3%; 1" in 48" = 2%. These are close approximations, but we're not doing prototype engineering where each half a percent has significant effect on how much train you can pull.