Baldwin 4-6-0 gear backlash

[dcross1]

I have a nearly new Baldwin 4-6-0 which, in my opinion, has too much gear backlash.  When running downgrades (3-4%) it lurches as the backlash is taken up then released.  It runs so well on level track that this problem is a big disappointment.  Is there any way to adjust or tighten up the gear backlash?

[p51]

I run sometimes on a large On30 layout and often run the guy's ten-wheelers. There's a substantial grade and to be honest, I hadn't attributed the 'back and forth' motion going downgrade to gearing in the locomotives until just now.
I only run the ten-wheelers on my own layout but I intentionally put no grades on my layout, so I never see this in action at home.

[Steve Magee]

In most cases, backlash is due to the armature in the motor that moves back and forward due to motor being reversed. Mostly this can be overcome by dismantling the loco and installing a thrust washer on the shaft next to the worm to limit travel. I do not have my 4-6-0 in bits at this time, so I can't help you with washer/shim thickness or the internal diameter of the washer.

Steve Magee
Lumber Mountain RR in On30
Newcastle NSW Aust