I was doing a run on Sherman Hill and when I was going down a 1.5 percent grade, I had to use the emergency brake from the automatic brake on top of full independent and dynamic brake application just to stay under the speed limit as if I kept the automatic brake under emergency it would just keep accelerating
They work well, just driver make some mistake. Read here: https://forums.dovetailgames.com/threads/heavy-us-freight-downhill-braking.52779/ or in other threads... You can go downdrade 1,5% in dynamic only mode with Intermodal and Automotive trains (easier variants for gaining experiences) My performance from today Intermodal Laramie-Cheyenne: (106 minutes)