Good Morning All,
I have two of the On30 4-6-0s that suffer from the same malady. When running down hill - even without a train behind - the engines run in a jerky motion similar to being in an automobile, going downhill, and pumping the brakes.
A friend, Tim Anders, who posts here, did some sound work for me in both the 4-6-0s(again, thanks Tim, VERY nice work!) told me that this is cause by gear lash. Tim told me that he has seen this problem with all the 4-6-0s that he has had his hands on.
Tim said to run the engines in reverse, pulling a train for several trips and replace the gear lubricant with LaBelle 102. Not sure if that is grease or oil. By doing this Tim says his 4-6-0 runs very smoothly now.
I am in the process of doing this now. Hope this helps others with the same problem.
Bob -
Interesting idea. What sort of grades are you running on?
-John
John,
I am really not sure, but I suspect I am running anywhere from 2-4%