Question: When driving a Diesel locomotive, is the independent brake used for slowing down but not stopping?
If you are a train expert or engineer I would like to hear your answer
No, if a lite engine, yes.
When moving the independent is sometimes used to bunch slack before going into dynamic brake, or when starting a train when the slack is in an unknown state (slack stretched or bunched or in disarray. The throttle is opened first, and the independent is slowly released, essentially creeping forward, until the whole train is moving. Try to stop a moving train with independent alone, all you'll do is burn off the brake shoes.
At slow speeds, as when switching, the independent can handle a significant number of cars with the air bled off. The key is the slow speed, which produces less inertia.
But most often when handling a larger cut of cars, the trick is to apply the brakes lightly and shove them under power. When you hear the signal to stop, you close the throttle and come ta a nice easy stop... on top of a dime.