I am working on an extension for my Stehekin, Lake Chelan & Glacier Peak Western R.R. in HO scale, and I’m planning a logging/mining branch line where the track switchbacks a few times. Also, on the main line, the track will loop up and over itself once. My maximum space requirements are about 5-6 feet square, but the problem is… What in heck is the formula for figuring grades? The logging/mining branch’s maximum grade should be 11% or less (This is Shay country!) On the main, maybe 4%… Can someone help? Thank You!
Rise/Run. For loops use 2(3.1416)(Radius)to determine run.
Hope this helps. Good luck
Hello WPYR221,
Mark’s given good formulas. For example, if the rise is 3" over 10 feet, you divide 3" by 120" (convert the run to the same increment as the rise) to figure a gradient of 2.5 percent.
You can also multiply: a run of 10 feet using an 11 percent grade gives a rise of 13.2" (120" x 11 percent = 13.2"). Using a 4 percent grade, a run of 10 feet is 120" x 4 percent = a rise of 4.8".
Remember to provide sufficient clearance where tracks pass over one another. The NRMA (www.nrma.org) has printable standards and recommended practices for minimum clearances.
Paul Schmidt
Contributing Editor
Trains.com
The easy way to remember grades is 1/2" per foot is 4%. So if you want a 1% grade then raise the track 1/8" for each foot of run. Now this not exact but it is close enough that you will not have problems. I just taped a wood dowel to one end of a 1 foot long level and then just raise the track until it shows level. Just use different size of dowels to get the grade you want.
BOB H Clarion, PA