I enjoy trying to get older n gage locomotives running again. I have a problem. I have about a half dozen Bachmann locomotives that are complete and have good motors in them but they won't run because the worm gear on the motor won't engage the spur gear that drives the wheels. This is true on engines that are clamped down between clips and also on engines that are held down via screws into a threaded hole on the bottom of the motor. Does anyone know hoe to fix this problem? 2 of the engines are 0-6-0 diesel dock siders. 4 are 0-4-0 steam engine switchers. The motors appear to be bedded down on their support pan. Thanks for any help you can provide.
It would be better if you tossed those and got new ones.
If, as I stated, I enjoy trying to repair older n gage engines, why would it be better to toss them and buy new ones?
Are the gears worn, or have the motors moved out of alignment? If it's alignment, there is an article in the new issue of Model Railroader where they rebuild an old N Scale 4-4-2. The author replaced the motor, but does go into a great deal of detail on aligning the motor to the gears. If they are worn I haven't any suggestions for you.
Thanks for your reply. I don't think the gears are worn. The problem is that the worm is too far above the gear
when the motor is installed. I know I could possibly shim up the rear edge of the motor to get engagement but I shouldn't have to do that. BTW, in some cases the worm clears the gear by 1/16 inch or more.
It sounds to me like there may be something keeping the outboard bearings on the worm shafts from setting down in the frame. Check the blocks that the bearing sleeves fit in. They may be sitting in the gear tower frame 90% off kelter. That would raise the worms too high.
Les
Thanks for the reply. There are no bearings for the worm on the 0-4-0 and 0-6-0 engines I am working on. The worm is on the motor shaft.
It depends on the version of the loco, there have been at least 5 variations I am pretty sure.
It sounds like the frame is warped or broken. There are no parts for these things so any cure you come up with will have to be something you make.
The funny thing is that I have the problem even with the original motor on the frame. The chassis doesn't appear to be bent. I wonder if, in addition to changing the frame, they changed some of the motor dimensions slightly.