I have a new layout and my locos wheels seem to be slipping a good bit. I have two Atlas gold diesels, one is 6 axel, the other is 4. I also have a 4 axle proto2000 diesel. They all slip pretty good. I don't want to replace the wheels. I would add weight, depending on where i can put it. Is there anything in the tank that is under the engine, or is it hollow? I don't know much about engines, as far as that goes. Any other treatment I could put on wheels that would increase traction without alot of conductivity loss? Thanks.