Ok gang I’ll though one at you?I’am getting reday to put a small second layer to my little railroad I want to go from O to 3"s in six feet is this do’able?? and what grade will this be???[:)][?][:)]
JIM
The grade is easy.
6 feet = 72 inches
3 inches / 72 inches = .0417
.0417 * 100 = 4.17% grade.
A bit steep but definitely do’able.
Doesn’t get much easier than Tex’s answer. I agree that the grade is “doable”, but it isn’t great. If you’re stuck with it, you’re stuck with it. If you can get one more foot out of that ramp, you and your locos will be happier with the grade reduction.
By the way, this is not so that you can cross a train over itself, is it? You will need 3.5" between the rail tops below to the lowest item above it. You still have trackbed and track to lay above that lowest point, so your grade will be that much worse.
4.17% ??? That is a mighty hefty grade. You might get the loco and a couple of cars up it. The prototypes tried their best to stay under 2% whenever possible. Even a 2% grade will cut down the number of cars an engine can pull severely. I would try your best to find another solution than to put in a 4% or greater grade.
Hope you have a geared Shay locomotive for that grade.[:)]
Patrick
I went up a 6% grade with a swicher and had to get off and push.
This was 7 1/4 inch gauge though. 
Yup I’ve got two geared shays,they should get-er done thanks gang!!
JIM[:)]
Remember you have to transition into and out of the grade so your 6’ may be more like 5’ making the grade 5% or greater. A straight line grade between two points is as stated above.
4% is steep.
Try to find 1-3 more feet to your grade… or even try to downgrade the other track so you wont have to climb as high as fast.