Some of you may have seen on FB that there is a guy up here in the Boston area, Jiro Yeramian, who is making replacement gears for USAT axles out of delrin to avoid the splitting issue. I visited him this morning to pick up a few, and was very impressed. He machines them by hand. I bought some for a 44 Tonner and PA-1. The PA-1 is the same as the other 6-axle locos, and he also has them for the 4-axle GPs.
They are $15 each, which adds up, but it sure beats trying to repair the original gears with sleeves or whatever.
His email is girotek at rcn.com