My home made 5 chime airhorns for the Bachmann DDA40X. I used a scrap piece of .010" styrene and drilled #71 holes in it in the pattern the trumpets needed to be. Next I cut the individual needed trumpes from some spare Kato horns I have and put them in the bracket I made. Then I glued it on the unit and painted it. I did have to widen the holes for the trumpets to be inserted, so maybe a #70 or #69 drill bit would have been better. It's not a fancy brass detail part but it looks better than that thing Bachmann glued to the roof.