How does UP number its locomotives?

UP4

 I have a spectrum DCC equipted sd45. When I run the loco, it will stall and then it will catch on and run and then stall. When it stalls, though, i can still hear the motor running. Has anyone had problems like this before?

I use a broadway limited blueline ac6000 loco with the ez command, but i'm upset that I can't controll all of the great sound effects. The ez command  can't controll cv's, but if you buy one of those mrc boxes that let you controll dcc effects and cvs with dc power, you can set up a cv programming track.

 Hey, i'm trying to find a dd40x locomotive, but i can't find any. Does Bachmann still offer them?