Just passing on information. I had a LionChief 0-8-0 "Southern Pacific Rising Sun" set loco start to have a hitch with each revolution of the drivers. (I suspect all of the LionChief 0-8-0's have this cammed driver regardless of paint scheme.)
I removed the pickup rollers and the plastic cover plate on the bottom of the frame.
The problem was that the cam on the front driver axle used to cause smoke chuffing was dragging on the part it pushes on with each revolution. This part is a free floating small rectangular bar called the "Smoke Push Rod". It is located in a rectangular vertical hole and pushes upwards into the engine's smoke mechanism area. The other end of the rod pushes on the "Smoke Lever" which is involved with mechanically making the smoke chuffs.
When I manually pushed on the visible end of the "Smoke Push Rod", I could not feel any movement. Don't know why.
Since this engine is used on a museum layout for children, we don't use smoke. So I could "fix" it by just removing the "Smoke Push Rod" which you can just pull out. Something is likely wrong inside the smoke mechanism area, but it doesn't matter in this case so long as the "Smoke Push Rod" is absent.
So if this happens to your engine, and you can live without smoke, it is an easy quick fix.
