dcc power adjustments

If you watch closely on some engines, and I'm sure I don't have all of the terminology right so please forgive me for the crude description, the two lower headlights on some engines alternate as they are approaching an intersection. On some DCC locomotives, is it possible to attain this without...

I'm adding to my general fund of knowledge with this question about DCC. If you were to run a DCC equipped loco with say 15 cars on a flat track at 20 MPH. Then the track started a 2% rise, would the loco slow due to the added strain of the cars being pulled up an incline? Or does DCC...