I just need a passing grade!

I’m setting up a small layout to run the circumference of my office about 10" down from the ceiling on a 6" ledge. I’d like to give it some ups & downs & was wondereing how extreme I could get with the inclines. Can I rise 3" in 57"?
Any help would be appreciated.
Jack
P.S. To start I bought a Bachman set “Irish Railway” and am just adding track. The room is 11’x9’

Grades are measured by the ratio of elevation vs. distance.
A 3% grade is 3 inches up for 100 inches out or 3 / 100.

You have 3 inches up for 57 inches out or 3 / 57 = 0.0326 or a 5.3% grade

That is pretty steep but would probably work. Just lay out some track on the floor with that grade and see if it will handle it. Be careful because if the locomotive has traction tires, the engine could work too hard and overheat. It is a good thing for the motor when wheels spin.

Generally with toy trains, I use the rule of thumb 3/8" per section of track is the maximum about 4%. 1/4" per section is approximately 3%.

7% is the practical limit for real (non cog or cable) railroads.