Hey folks. Thought I'd pop in for some help with a problem. I just purchased a Rivarossi Big Boy, one released in 1975. Before running it I lubed all the necessary points. But when I try to run it, something weird happens with the rear truck. The shaft turns for a bit, maybe halfway through a full rotation, when the rear truck begins to turn out away from the engine. Then the shaft stops turning. As a test I held the engine and gently turned the shaft, and watched as the truck turned out away from the engine. Why in the world would the turning shaft cause the truck to do this? Any ideas on how to fix the problem?