You can create 3D stairs and railings using Revit Architecture. But how do you change the height of the handrail? The most obvious answer is to select the railing (System Family: Railing) and go to type properties. You will see a Height type parameter under Handrail 1 set to 3'-0" but it is a read-only value. Read-only? Now what?
If you want to adjust the height of your handrail, you must select the handrail (System Family: Handrail Type) and not the railing. How do you that? Easy, simply hover over the handrail and use the TAB key to highlight the handrail and then left click to select just the handrail. Now go to type properties for the handrail and change the Height type parameter to 2'-10" or whatever height you want!