A rare flat-top 3 chime whistle stated to be from the Chicago & Northwestern railroad. A few other examples of this whistle survive today. The CNW later adopted and replaced the 3 chimes on most of their steam power with a step-top 5 chime. A 3 chime, most likely recovered from a CNW steam locomotive that was being scrapped, fell into the hands of the Rio Grande. The whistle was used on K-28 #478 from the 1960s until 2003, when it was replaced with a D&RGW 5 chime and installed on sister loco #473, which it has had to this day.