It's puzzling why CLW delayed the HOG addition to WAP4's so much. The three phasers at least provided several challenges to CLW initially that had to be solved before even using the loco for normal operations ( Both P7 and P5 had so many initial struggles) and so it's understandable that these new enhancements took some time to materialize. The WAP4 design was something CLW was very familiar with and there was nothing new for them to worry about. They should have come out with a HOG system for it long ago!