As I recall Lionel was not happy when the Moguls were returned. They still had issues and many returned theirs for a refund. I was fortunate to find three that had not been returned to China plus the one that John has. Those could be made to run fine by eliminating the excess clearance in the front siderod. Thinner traction tires are icing on the cake but probably not needed. The TMCC and conventional Moguls run smoothly with their fat traction tires on the front driver.
Pete
