If your friend has the Annie instrucion sheet, it has an Exploded view of the Annie. You should be able to get the part number off the sheet and contact Bachmann and get it from. If you don't happen to have one ( the instruction sheet ) I can scan and email you a copy of mine.
Part numbers on Bachmann instruction sheets are pipe dreams at best.
They probably mean something in China, but nobody in Philly has any idea what they mean.
Those sleeves have been splitting for a long, long time.
IF you can find styrene that works, great.
I super-glue them together with the axle in place, just before I put BBT 2-8-0 chassis under them.