Gradients

[Maxx02]

I have a 9 ft x 9 ft plan but I'm not sure what is an acceptable gradient for an HO train.   I'm planning a U-shaped layout with a duck under at the top of the U so that I can have one track that completes a circuit.   I planned to have the duck under at a reasonable height above the bench so that I don't have to crouch too much.    I wanted the train to climb the long arms of the U as it approaches the duck under.    Does this make sense?

What would the gradient be as it approaches the duck under and how high would the duck under be above the bench?

[RhB_HJ]

If you "love" your engines keep it below 3.5%.

[Maxx02]

Thanks for that.   AnyRail defaulted to 4% and I wasn't sure if that was a normal baseline start point or what.   I'll try 3.5% and see how that looks.

[chaz]

Maxx02,

One construction method is to use Woodland Scenics has risers.  They come in 2%, 3% and 4% grades.  Here is their how to use them guide.
http://woodlandscenics.woodlandscenics.com/images/instructions/InclineInst.pdf?KeepThis=true&TB_iframe=true&height=500&width=800 

Chaz