This isn't so much a locomotive request as a feature request; would it be possible to see the brake cylinders extend when we apply the brakes on the locomotive? Dunno if that's even possible in the game, but would be neat for those of us who like to switch from ground-view.
How about some good old fashioned EMD covered wagons with opening doors?
EMD GP20 hood units?
JR use to have an ex Southern SD40-2 as payware a long time ago but they retired it and took it down.