One quirky problem on two different train cars.
First was a K-line steam passenger set i bought a few months ago. It has a Railsounds tender. Out of the box the sounds were intermitant as it rolled down the track. I turned the tender over and inspected the wires, oiled the axles, and jimmied the sensor. Nothing fixed the problem. After a few days and some frustration I noticed a tiny grease blob on the axle with the sensor. The grease had hardened somewhat and was keeping the axel from turning easy. With a swipe of a rag it was gone and the problem solved.
Flash forward two months to my latest train item, a MtH passenger set. Unpacked the cars an gave them a test run. Everthing was fine except the observation cars lights flickered. Checked all the connections and bulbs. Still flickered. Long story short - there was a build up of grease on the axles under the ground contacts. Cleaned off the axles - problem solved.
Is anyone else running into this? Do axles really need grease at these points?
Maybe this can help others if they have these problems.