One of my Lionel Legacy diesels (New Haven #8696), occasionally starts up when I am addressing another engine. It starts moving; and when I stop it with the controller, it will start moving on its own again. It's almost as if there was a little gremlin in the engine that is controlling it. This does not happen all the time; and most of the time, it works properly.
Now, I am not sure if this is connected to the problem; but sometimes my controller has the message "can not find base"; and when that message appears, I can't run any Legacy engines. When I shut everything down, wait a while and re-start things, that message disappears and everything works well.