Somewhere (on this board I think) Is an involved tutorial on setting the speed curve. That was supposed to help get the Chuff Rate close, but it was never perfect. What scale are you? If using the "G" module, you can trigger chuff with a reed switch and a magnet, or a locos built in chuff switch. It's still not perfect, but once you learn how to "play" the speed when accelerating and decelerating, it's pretty good.
