My son and I were testing a ZW transformer in preparation for our Christmas layout. We noticed that the whistles were not working so we pulled the cover and discovered that it appears to have no whistle diodes, or rectifiers, or whatever the proper name is. Our old ZW was always splitting the diode into two pieces when we blew the whistle so we replaced the ZW with this one. I guess I didn't realize that they made ZW's without a whistle.
Is it possible to outfit the ZW with a whistle?