Yesterday I was finally able to run some trains around the perimeter of the lower deck layout I am building. That perimeter track involves a few ramps up one portion of my viaduct, and down another. I was test running with plain DC power, and the trains would slow down quiet a bit while climbing, and speed up while descending. 

Does DCC operation do any adjusting of this engine speed automatically? ...or can it be programed to do so??

I am in the planning stage of a shelf switching layout that our grandson ( 5 years old at this point) and I can spend time operating.  I will be using an NCE Power Cab (given to me by a friend who updated his home layout). I am looking for suggestions for a 4-axle early generation locomotive (GP-7/GP9 type that is DCC with sound.  I am looking for one without too many options. 

Since this will be a switching layout low speed performance is desired while high speed is not necessary. 

I’m fed up with my Digitrax PR3. Every time I try to use it becomes an all day process to get it set up and working. I never really know what I did to make it work when it does. I got to the point where I won’t shut down my computer once it’s running for fear of having to set it up again. But ultimately something happens and the connections is lost and I’m back to another wasted day trying to make it work.

Referencing the plan of my harbor module below, you can see the short passing siding/runaround. I had only planned on using one panel switch to control both remote machines on each end but now I'm wondering if each turnout should have it's own panel switch. I can't really imagine why I would ever want to throw the machines separately but I want to consider all eventualities. What do you guys think?