I am grateful for this forum! I don't know where I would find answers at if not. I just bought my first train set with DCC locomotives. EMD GP40 and EMD FT-A locomotives. (by the way I have no idea what those numbers mean) I would love to know how and what sound systems are compatible with these. Also maybe what number or style of couplers they use. I know they are knuckle couplers but I've seen several makes like kadee but there are different types also