Hi Kathy/Duke, I think the protosound plug in is a new board you would get an install. There is no need to do that now since the existing sound should have horn and bell. The railsounds would give you additional engine motor sound, but is not required. I believe this is what the instruction book mentioned. Allan From: ttat-members-owner@aoot.com [mailto:ttat-members-owner@aoot.com] On Behalf Of K Bischoff I have a Rail King Santa FE Dash-8 3- Rail Diesel Item # RK -2004 In box. Box says it accepts plug- in protoSound System. Can I have this done or is it something I could do ? I want to do this as a Christmas gift to my grandson Zachary. Thanks Kathy and Duke |