HI Folks: First Off, I am posting similar messages on several of the sub forums in The Ready Track, if this is wrong, please accept my apologies. Im planning a model railroad based loosely on the San Luis and Rio Grande. I am looking for information about the signaling protocols used in the area, in this case, specifically the KCS. I realize that in-cab signaling and PTC are to some degree replacing external signal lights, but for my layout, I would like external signals, but what I am having a difficult time finding information about is the different signal aspects and their meanings. Does anyone have this information and / or some links? Thanks TIM San Luis and Rio Grande