We have tons of sounds and features packed into our decoders, but how do you choose the right decoder for your model? Steam and electric are easy. All of our steam sounds are on one decoder and all of our electric sounds are on one decoder. All you need to do is determine the board format that will fit in your model and then select steam or electric. Diesel is a bit more difficult. We have so many diesel sounds that they cannot all fit one one decoder. Therefore we have broken our diesel decoder