The specific probelm is if I have a run of 3 3/4" and a drop at 5.35%, how much is that. Reason is I am building the end of a coaling ramp and the sooner I start the grade, the lesser the grade will be 1/8" here and there adds up.
A 5.35% grade over 3.35 inches is about .2 of an inch rise(or drop if measuring from the high point). Are you sure you mean 3.75 inches?
Is the run 3 and 3/4 inches, or is it 3 feet plus 3/4 inch? And what is a "drop" at 5.35%?
If you are saying your percent grade is 5.35 percent, this means that your track will slope down 5.35 inches for every 100 inches; 2.675 inches for every 50 inches; 1.338 inches for every 25 inches; and 0.054 inch for every inch.
So if your run is really 3.75 inch, you would multiply 3.75 inch by 0.054 inch/inch and end up with 0.203 inch. This is about 13/64 inch.
If indeed the run is 3 feet 3/4 inches the rise, (or drop) would be 1.98 inches.
i'm also confused by the numbers
does it really matter what the grade is as a %? don't you have a limited horizontal distance (the run) that has to climb some vertical distance (the rise or drop)? don't you want to maximize the horizontal distance to minimize the grade?
greg - Philadelphia & Reading / Reading
OP needs to tell us two things, how high is the top edge of the coal ramp and what is the maximum distance from the top edge of the ramp to the point where he can start the incline, the longer the starting point is from the ramp the lower the %.
Don't forget that the transition from flat track to sloped track is extra length added, at less than the main sloped part. That will either reduce what rise is achieved at the max height end (if the horizontal run is kept the same) or increase the total length needed past the flat track somewhat if the total height is to be achieved. A third option, within the desired run of track, is to increase the main slope slightly to make up for the less than average transition slope.
Of course, if the track goes from flat to sloped but flat again at the top end, two transitions are included which doubles this effect.
Paul
Modeling HO with a transition era UP bent
Thank you, and yes it is a small space with transition happening in the space before. Only ore cars and such will be backed up on the dump. I have no math skills to speak of but not bad on investing so I needed to turn to you people. In building a model railroad, you just never seem to have enough room.