thanks for the tip.  in checking this thing out further i found one wheel had to be moved in and the other moved out. so when the right side wheel hits the frame b4 the gears disengage. i still would like to see a wider idler gear. if only .010 to .015 inch.

looking for compound gears for rivarosi y6b. 18 toothand 12 teeth .060" bore x .053" accross or broken engine for parts. n scaller

don't get rid of your rivarossis . keep them lubricated.(i didn't)don't look like any thing will out pull them.  n scaller

i have had three class j locos 2 were replacements. still no satisfaction. i have $230 invested in a $160.00 loco. this one i decided to repair myself because it costs $20.00 to return it and get another defective engine. what i have found with this one is. it runs then stops. reason. the second drive axle can slide sideways and become disengaged from the idler gear. i have called Bachmann service for help. they answer the phone and say they need to refer me to some one else. who turns out to not be answering the phone and it says leave a message. i leave a phone no. and name they call back a day or two later. and say i need to talk to someone else. who isn't at their desk either . this has gone on for better than a week. still waiting for a call. it seems if the idler gear were .010" thicker all would be ok. if i ever here from Bachmann i wold like to procure another idler gear ,align them and super glue them together . put them in a miniature milling machine and shave off enough till i get a working thickness. does any body else have any suggestions?  n scaller