I've noted something that Brian Scace from OST has said a number of times. Some greases are thick and allow pockets to form and some greases/oils flow which allows the grease/oil to move back onto the gears which is what we want. I use both. The red and tacky seems to form pockets in my opinion but I do use it. The LaBelle seems to have some flow but it does seem to get dirty very quickly which is somewhat alarming. I dunno. If you are diligent about pressuring Red N Tacky into MTH frames until it oozes out the sides, of course it will be fine.
It seems like the ideal would be a heavy oil that is dripped in from above, the gears run through a trough picking up liquid on each revolution, while any sediment washes to the bottom due to gravity. Remove the bottom plate, remove any sediment and re-oil. I think this is how Midwestern works but he does diesels so I'm not all that sure.
Whenever I have an open house, most of the engines on the layout get their gear boxes checked out and greased. I guess I'm in the camp of routine maintenance is best. I don't have any plastic gears which might make a difference for some people.
