The Track Cleaning car is #3927
I believe the replacement sponge kit came with a double-sided tape that the sponge was pressed onto, and then that assembly was pressed onto the Drive Arbor:
http://www.ttender.com/weblistpictures/3927-25A.jpgWithout the double-sided tape, you can try using rubber cement. It is thick, and won't get absorbed by the sponge.
Larry