One of the traction tires on the front truck of my American Flyer U33C (first generation) broke and came off. Unfortunately I don't have the remains of the tire that came off. The spares that came with the locomotive include two different sizes. There is a larger diameter one that is narrower in width and a smaller diameter one that is wider. The rear truck that still has the original tires appears to have the wider tire on one wheel and the narrower tire on the opposite wheel. Any information on what tires to use and in what position would be appreciated.