Looking for old Empire Builder gears

[Glassguy4u]

Hi all!  I have an old N scale Empire Builder Steam that needs new nylon gears!! Part #7971. Unfortunately Bachmann said they don't make them anymore!  Does anyone on here have any?  I actually have 2 engines, so I need double!!! I love this 4-8-4, but, I bought one new years ago and found this 2nd one on ebay:( AND THEY BOTH HAVE THE SAME PROBLEM!!!...The heels keep falling out!  Or does anyone have a solution to the problem??? I've attached a pic of the problem.... any suggestions GREATLY appreciated!!!!