Because DCC is a digital system, discrete speed steps define locomotive speeds. The DCC standard calls for 14 forward and reverse steps for speed control. Some decoders offer advanced 28-step operation to give you even more speed control. And if that’s not enough, how about 128 step operation. With 128 step operation you have extremely fine speed control. You can really make those locomotives crawl! The ability to take advantage of more speed steps depends on the throttle you are using. The number of speed steps a particular decoder can use is determined by the manufacturer, some systems use CV29 to set up which mode the decoder will operate in.