|
Post by Packer on Apr 6, 2014 20:06:21 GMT -5
I recently purchased a three new Athearn RTR SD40-2s. I noticed one of them rocks a lot when reversing directions, or starting up. I tried shimming the area where the worm gear covers but that didn't help much. The trucks aren't warped, but I noticed one of them has a lot of play in the axle bearing area. I placed in on a window and a mirror (no plate glass) and was able to rock it a lot without the wheels coming off the glass...
I checked my other locos and have noticed some others have the same problem. The only other one I noticed was an atlas U33C.
Is it possible to shim the axle bearings on an Athearn to have less play without losing electrical contact for that truck? Or should I follow the advice of a MRR club member and use a high momentum when I install a decoder? My father was observing me tinkering and he said it's motor torque. But he's not into model trains (more into building and tweaking cars for racing) but it does kinda make sence.
|
|
|
Post by CP_8530 on Apr 7, 2014 1:10:25 GMT -5
I've run into an Athearn or two with a bit of rocking in the wheelsets - usually it's the top of the truck where the bolster meets that is slightly off, causing the loco to rock (fixable by shimming or filing or bending the contact strip), but I'm not sure about what to do when it's the axles rocking in the trucks. That to me suggests the gear is pushing the axle down in such a way the bearings aren't sitting fully in their pickup slots.
|
|
|
Post by Mark R. on Apr 7, 2014 1:28:24 GMT -5
The wheel sets won't rock due to directional torque - it's the chassis torquing on the trucks. Like Dan says, it's the plate on the top of the truck. In my reply to you on that "other forum", one truck should hold the chassis steady and the other should be allowed the rocking action to traverse uneven track.
I'd be willing to bet one plate is bent slightly to the left and the other truck plate is bent slightly to the right and the chassis is rocking back and forth between the two level points. You need to adjust them so they are in the same plane.
Mark.
|
|